Congenital absence of the brain and spinal cord.
The congenital absence of the spinal cord.
A distinct almond-shaped part of the brain’s limbic system, involved with smell and behaviour.
A starch-splitting enzyme. (See DIGESTION, ABSORPTION AND ASSIMILATION.)
The deposition of an insoluble starch-like protein (amyloid) which affects the functioning of the tissues in which it is deposited. It may be associated with inflammatory conditions or chronic infections.
Relating to anabolism, which means tissue building, and is the opposite of catabolism or tissue breakdown.
An anabolic steroid is one derived from testosterone in which the androgenic characteristics have been reduced and the protein-building (anabolic) properties increased in proportion. Examples are nandrolone and ethylestrenol. These are used in cases of malnutrition, wasting diseases, virus diseases, and severe parasitism.
Synthetic anabolic steroids have been used as growth-promoter implants in commercial beef production, but this is prohibited in the UK and EU. They are also prohibited in competition animals. It has been found that anabolic steroids can give rise to changes in the liver and its functioning in both animals and man; with, in some instances, tumour formation. Changes in the sexual organs may follow misuse. (See STILBENES.)
A developmental abnormality in which the lower extremities of two fetuses are joined together.
An anadromous fish is one that spends most of its adult life in the sea but returns to fresh water to spawn. Salmon are anadromous.
A reduction in the number and/or size of the red blood corpuscles or the haemoglobin in the blood. It is a sign rather than a disease, and it is important to establish the cause (obvious only in the case of acute external haemorrhage due to trauma), so that a prognosis and suitable treatment can be given.
The animal may be suffering from a chronic loss of blood due to internal bleeding, e.g. from the urinary or digestive tracts; and the owner of a cat, for instance, may fail to notice the presence of blood in the urine, and so not bring the animal for treatment until other signs of illness have become obvious.
Anticoagulants, such as Warfarin, may cause internal haemorrhage and hence anaemia.
An iron-deficient diet (and one lacking also the trace elements cobalt and copper, which aid the assimilation of iron) is another cause of anaemia; likewise a deficiency of folic acid, vitamin B6 and vitamin B12.
Both external and internal parasites (lice, fleas, ticks, liver flukes, roundworms and tapeworms) can cause anaemia.
Parasites of the bloodstream are an important cause, and include trypanosomes, piroplasms and rickettsiae. (See also FELINE INFECTIOUS ANAEMIA.)
For an incompatability between the blood of sire and dam, see haemolytic disease (under FOALS, DISEASES OF).
Aplastic anaemia means a defective, or a cessation of, regeneration of the red blood cells; it may be drug-induced. (See also RETICULOCYTES.) (In human medicine, the drugs involved have included chloramphenicol, phenylbutazone, and rarely penicillin and aspirin; deaths have resulted.)
Bracken poisoning, exposure to X-rays or other forms of irradiation are other causes; also salicylates (including aspirin).
In auto-immune haemolytic anaemia the animal forms antibodies against its own red cells.
Heinz-body haemolytic anaemia (see HEINZ BODIES) may result from kale poisoning in cattle, and from paracetamol or methylene-blue poisoning in cats; sometimes also from lead poisoning.
Signs Pallor of the mucous membranes, loss of energy and of appetite, and PICA. Dogs and cats may feel the cold more than usual, and seek warm places. In some cases fever is present, and liver enlargement. The heart rate may increase.
Treatment In the smaller animals especially, vitamin B12 or liver extract is often a valuable method of treatment. Where cobalt or copper or iron are lacking, these must be supplied. Lice or ticks and fleas should be destroyed, and treatment against internal parasites undertaken if they are the cause. Blood transfusions are useful provided donor and recipient are compatible. Anaemias due to specific causes have specific treatments. (See also PIGLET ANAEMIA; FELINE and EQUINE INFECTIOUS ANAEMIA; CANINE BABESIOSIS; HEARTWORM; ROUNDWORMS; FLUKES AND FLUKE DISEASE.)
(adjective, Anaerobic)
The term applied to bacteria having the power to live without oxygen. Such organisms are found growing freely, deep in the soil, as, for example, the tetanus bacillus.
The use of general anaesthetics to produce loss of consciousness and sensation for operations on animals dates back to 1847, when several veterinary surgeons first used ether. Chloroform was also first used in 1847. Both have now been superseded by safer anaesthetic agents. A wide choice is now available. The choice, dosage and means of administration will be influenced by such considerations as the species, size and habitat of the individual, as well as by the procedure to be undertaken and the availability of equipment. Unconsciousness, abolition of reflexes and muscle relaxation are the key requirements of anaesthesia. In overdose, respiratory paralysis occurs due to depression of the respiratory control centres in the medulla. General anaesthesia can be induced by inhalation of a volatile or gaseous anaesthetic, or by intravenous or intramuscular injection. Inhalation anaesthetics are often administered via an endotracheal tube. Anaesthetic agents are often used in combination with a premedicant, such as acepromazine or an alpha-2 agonist drug.
‘Balanced anaesthesia’ is the use of smaller doses of a combination of two or more drugs to achieve the various stages of anaesthesia, thus avoiding the disadvantages of using large doses of any one drug. Muscle relaxants may also be used to facilitate certain procedures. If the animal is a food animal, care must be taken to observe any precautions indicated by the drug manufacturer to avoid drug residues accumulating in meat or milk. In all cases, the manufacturers’ recommendations as to dosage must be followed.
This technique depends upon the introduction into the trachea of a tube which is then connected to an anaesthetic machine. The tube is passed via the mouth following an injectable anaesthetic, such as a barbiturate, propofol, alfaxalone, ketamine, etc., and is then used as the route for administration of an inhalant anaesthetic mixture. The method ensures a clear airway throughout the period of anaesthesia, and thus obviates the danger of laryngeal obstruction (e.g. by the tongue falling backwards), which sometimes causes death. The method has several other advantages, e.g. it permits an unobstructed operation field during lengthy major operations especially of the head and neck, achieves better oxygenation, facilitates an even level of anaesthesia, and permits use of respiratory monitors and of positive pressure ventilation of the lungs in the event of respiratory failure. As an alternative to general anaesthesia, EPIDURAL ANAESTHESIA (involving the injection of a local anaesthetic into the spinal canal) is used for some surgical procedures in large animals that are easy to restrain, and may be used to provide extra analgesia during general anaesthesia. (See ANAESTHESIA, GENERAL - ‘BALANCED ANAESTHESIA’ above.)
Cattle Most procedures are performed under local anaesthesia. Where general anaesthesia is indicated, after premedication with, for example, xylazine, and induction of anaesthesia with ketamine, isoflurane or secroflurane is administered via an endotracheal tube. Endotracheal intubation is recommended in order to preserve a clear airway, and to prevent inhalation of regurgitated rumen contents.
Horses General anaesthesia is normally induced by intravenous injection of ketamine and diazepam after premedication with xylazine, romifidine or detomidine and maintained by inhalation of isoflurane or sevoflurane, administered through an endotracheal tube. Ketamine must not be used as sole anaesthetic in the equine. The use of thiopental, via intravenous catheter, also requires premedication. Great care must be taken that the recumbent anaesthetised horse does not suffer muscle or nerve damage, caused by the pressure of its own weight, while unconscious.
Sheep No anaesthetic drugs have a market authorisation for sheep and so must be used according to the ‘cascade’. Ketamine, propofol and alfaxalone given by slow intravenous injection have all been used for induction of anaesthesia. Isoflurane may be given by inhalation.
Goats Alfaxolone, propofol, ketamine and isoflurane, and sevoflurane have also been suggested for such procedures as the disbudding of kids. Xylazine (usually diluted) can be used but hypothermia needs to be prevented. For long procedures anaesthetised goats should be intubated. Again, no preparations are licensed for this animal.
Dogs and cats A wide choice is available. Propofol, alfaxalone and thiopental by intravenous injection rapidly induce general anaesthesia in action. Ketamine, given by intravenous or intramuscular injection, is another choice, but it must never be used alone without adequate premedication. When given to cats, it is often used with metomidine to prevent excitability on recovery. Propofol, an intravenous anaesthetic for dogs and cats, is very commonly used for minor outpatient procedures and CAESAREAN SECTION. Recovery is generally smooth but retching, sneezing, and pawing of the face may be seen.
Monkeys Ketamin is often used given by subcutaneous, intramuscular, or intravenous injection after suitable premedication. Tiletamine/zolaze-pam (Zoletil) is a similar drug combination which has proved useful. Isoflurane is suitable for maintenance of anaesthesia. The choice usually depends on the ease and safety of restraint in individual animals
Rabbits, rats, mice, guinea pigs Inhalation anaesthetics such as isoflurane and sevoflurane are safe and effective; but rabbits should be sedated first. Injectable anaesthetic combinations, such as fentanyl-fluanisonle and midazolam, or ketamine and xylazine, may be used.
Birds Isoflurane is the most suitable. Intramuscular injections of ketamine with or without xylazine may be useful when anaesthetic machines are not available. Restraint must be carefully considered so that the movement of the sternum is not impaired.
Reptiles Small reptiles may be anaesthetised by inhalation of isoflurane or sevoflurane. Large lizards, tortoises and snakes are best induced by intravenous propofol, intubated and maintained with isoflurane or sevoflurane. Positive pressure is usually required as reptiles seldom breathe spontaneously under anaesthesia. Ketamine by intramuscular injection is also used but recovery may be prolonged. Due to the ectothermic nature of reptiles, maintenance of the animal’s optimal temperature and a patent airway are essential until the animal is breathing spontaneously.
Fish Phenoxyethanol, benzocaine or tricaine mesilate, dissolved in the water, are commonly used for both exotic and farmed fish. Exotic fish species vary in their tolerance to these substances; water temperature and quality also affect their efficacy. Clean oxygenated water should be available to aid recovery.
Camelids A combination of xylazine, ketamine and butorphenol by intramuscular injection may be used for short time surgery.
Pigs A combination of xylazine, ketamine and butorphenol by intramuscular injection may be used.
For many minor operations and diagnostic procedures, local anaesthetics are used in preference to general anaesthesia. They act by blocking conduction along the nerve fibre, producing loss of sensation and/or muscle paralysis. Drugs used include lidocaine (lignocaine), procaine, ropivacaine and bupivacaine. The method and site of administration can be targeted according to the specific procedure to be carried out.
Perineural anaesthesia is used when the precise location of the nerves serving the area to be anaesthetised is known. For example, when disbudding calves, the area may be anaesthetised by injecting the agent above the corneal nerve between the eye and the base of the horn bud.
A field block can be used for anaesthetising large areas. A series of injections is made along a line (including skin, subcutaneous structures and sometimes muscle) to remove sensation from the tissue along that line. An example would be desensitising of the flank for CAESAREAN SECTION and RUMENOTOMY. Regional anaesthesia results from perineural or epidural anaesthesia. To anaesthetise a limb, a tourniquet is applied above the part of the limb to be anaesthetised and the drug given intravenously; lidocaine is the agent of choice. This technique is termed intravenous regional anaesthesia (or sometimes Bier’s block). Loss of sensation lasts until the tourniquet is released. The precautions applying to the use of tourniquets must be observed (See under TOURNIQUET). Surface anaesthesia is useful for facilitating certain procedures. It may be applied to a mucous surface by spray. For example, a cat’s throat may be sprayed with lidocaine before introducing an endotracheal tube. To facilitate introduction of a venous catheter, the skin of smaller species can be anaesthetised by applying an anaesthetic cream, after shaving the area. The cream is protected by a waterproof dressing; the anaesthetic may take up to an hour to work.
Local anaesthetics may also be administered in eye drops. The cornea of an animal can be anaesthetised by local anaesthetics (e.g. tetracaine or proxymetacaine) sufficiently to perform minor procedures such as cauterisation of a shallow ulcer. The use of regional anaesthetic in small animals is usually as an adjunct to general anaesthesia. Epidural anaesthesia results when a local anaesthetic is injected into the space surrounding the spinal cord – the epidural space. This produces a loss of sensation in the tissues served by the spinal nerves. The specific area affected depends on the site of injection. In the caudal epidural space, anaesthesia of the perineal area results; the technique is used e.g. in difficult calvings.
Epidural anaesthesia applied to the lumbosacral epidural space may be used for operations on the recumbent animal. Intra-articular anaesthesia, by injection into a joint, is mainly used diagnostically to identify a joint that is causing pain. Local anaesthetics must not be used indiscriminately since poisoning can result, and affect the brain and heart. Signs of poisoning include sudden collapse, or excitement, vomiting and convulsions.
The Protection of Animals (Anaesthetics) Act 1966 made it obligatory to use an anaesthetic when castrating dogs, cats, horses, asses and mules of any age.
Castration Only a veterinary surgeon, using an anaesthetic, is permitted to castrate any farm animal more than 2 months old; with the exception of rams for which the maximum age is 3 months and in goats only use of rubber rings under seven days old can be done by stockpersons.
The use of rubber rings or similar devices for castrating bulls, pigs, goats and sheep, or for docking lambs’ tails, is forbidden unless applied during the 1st week of life. The Act of 1966 also requires that an anaesthetic be used when dehorning cattle; and also for disbudding calves unless this be done by chemical cautery applied during the 1st week of life.
An anaesthetic must be used for any operation, performed with or without the use of instruments, which involves interference with the sensitive tissues or the bone structure of an animal. (See also DOCKING.)
Dogs and cats have shown severe signs of poisoning after being fed on meat from animals humanely slaughtered by means of an overdose of a barbiturate anaesthetic, or chloral hydrate.
The period of active hair growth by the hair follicle. (Compare TELOGEN)
A congenital anomaly wherein twins are divided above and below but joined in the middle.
Relating to the ANUS.
A common, if technically incorrect, term to denote an anal sac that has become infected and has fistulated to the exterior.
(See ATRESIA ANI.)
Drugs that stimulate the central nervous system (See STIMULANTS).
(See under ANAL SACCULITIS and ANAL FURUNCULOSIS.)
A condition of the dog, particularly common in GERMAN SHEPHERD DOGS, in which discharging sinuses develop around the anus, allegedly caused by friction of the heavy tail on soiled skin, but perhaps follows the trapping of faecal matter in the folds of the anal MUCOUS MEMBRANE. Surgery may be required to assist resolution of this painful condition.
Drugs which cause a temporary loss of the sense of pain without a loss of consciousness, i.e. analgesia.
Analgesics include non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin, carprofen, flunixin, meloxicam, paracetamol and phenylbutazone. (They are contraindicated if animals that have heart, kidney or liver disease and some are particularly toxic in particular species, e.g. paracetamol in cats.)
Opiates are analgesics, the most effective of which is MORPHINE. (See also BUPRENORPHINE HYDROCHLORIDE; DETOMIDINE; ACUPUNCTURE.)
Dogs, cats and other species (including the family Mustelidae) possess two sacs on either side of the anus into which open numerous APOCRINE and SEBACEOUS GLANDS, which produces a malodorous fluid, a PHEROMONE. (See also under ANUS.)
The ANAL GLANDS may not always empty properly and swell, cause pain and become infected. This is presented by the animal pressing and dragging the PERINEUM along the ground. There is often licking of the affected part and crying. Pressure and friction may result in formation of fistulas on one and both sides of the anus - ANAL ABSCESS or ANAL FISTULA.
Anamnesis is the past history of a particular patient.
The rapid rise in antibody level in a previously immunised animal in response to a ‘booster’ dose of the same vaccine. The immune system has ‘remembered’ what to do.
Impairment of sexual appetite.
The reaction to a foreign protein which sometimes follows bee or wasp stings, injections of an antibiotic or antiserum, etc., after the patient has become hypersensitised to the substance. There is often a rapid fall in blood pressure; anaphylactic shock can prove fatal. (See also ANTIHISTAMINES; HYPERSENSITIVITY; WARBLES.)
This is an infectious disease of cattle, characterised by anaemia and caused by a parasite of the red blood cells, Anaplasma marginale.
This parasite is found in Africa, Asia, Australia, Southern Europe, South America, and the southern States of the USA. A. centrale (in cattle) and A. ovis (in sheep and goats) are other species.
Signs The disease resembles Texas fever; frequently anaplasmosis coexists with babesiosis, but pure infections may also occur. It is characterised by acute anaemia, fever, jaundice, and degeneration of the internal organs; haemoglobinuria does not occur as the rate of red-blood-cell destruction is not fast enough to produce free haemoglobin in the circulating blood. Young animals appear to be resistant, and cases in calves under 1 year old are rare. In older animals the disease may be acute or chronic, and in the former case they may die within 2 to 3 days after the appearance of the first signs. The disease starts with a high temperature of 40.5° C to 41.5° C (105° F to 107° F) and after a day or two anaemia and icterus appear. In the acute illness, aggressiveness and abortion are other signs.
Transmission is by ticks, e.g. Boophilus, Rhipicephalus, Hyalomma, Ixodes, Dermacentor, and Haemaphysalis. Infection is passed through the egg to the next generation of ticks. Tabanid flies and mosquitoes are carriers.
Animals which recover from anaplasmosis are in a state of premunition, and remain carriers for long periods, probably for life.
In the South African States the less serious A. centrale has been found to give protection against the serious A. marginale, and both there and in other countries successful results follow its use as an immunising agent. In other areas where Texas fever and anaplasmosis frequently occur together, cattle are often immunised by blood of a bovine infected with A. centrale, which produces a mild infection, and with a mild form of Babesia bigemina. Treatment of anaplasmosis is by oxytetracycline injections.
Anasarca is a condition of oedema, particularly of the tissues below the skin. The fetus can become anasarcous from a genetic predisposition, most frequently seen in Ayrshire cattle, and can lead to abortion. Otherwise the fetus can become larger than the birth canal, so that a CAESAREAN SECTION is needed to deliver the calf.
The means by which the circulation is carried on when a large vessel is severed or its stream obstructed. In anatomy the term is applied to a junction between two or more arteries or veins which communicate with each other. It is also a term for the surgical repair of a tubular organ such as the intestine.
A toxin rendered harmless by heat or chemical means but capable of stimulating the formation of antibodies.
The absence of the nose and olfactory centre of the brain.
(Lernaea cyprinacea) An exotic parasite of goldfish now to be found in some indoor ornamental pools in the UK. The worms can penetrate the fish’s skin. Their removal needs to be done under anaesthesia.
A breed originating in Ancona, Italy and present in Britain since the late 19th century. They produce white or blue-tinted eggs depending on the genetics, laying about five per week. The plumage is mottled black with white tips to the feathers. The combs are single and red and they are lopped in the females. The legs are not feathered. The standard cocks weigh towards 3 kg (6 lb) and the hens up to 2.5 kg (5 lb). They are a useful backyard or pet hen.
Part of the elbow joint, being a projection of the ULNA. In several breeds of dog it may not develop properly
(See HOOKWORMS.)
These horses were bred in south west Spain from the old Iberian horses and Arab imports. They made good war horses, particularly favoured by the Romans, and now are popular as riding mounts. In Spain they are used in bull-fighting. They are normally bay, black and grey.
Any steroid hormone that promotes male characteristics. (See HORMONES.)
The female pseudohermaphrodite.
Female pseudohermaphroditism, usually of hormonal origin.
This hormone is produced in the ADRENAL GLANDS, ovaries and testicles as an intermediate step in the production of OESTRADIOL AND OESTRONE and testosterone.
A metabolite of androsterone which contributes to BOAR TAINT.
An androgenic hormone excreted in the urine.
The absence of genital organs.
A defect in which an animal is born without a brain. This may be congenital or from exposure to a teratogenic substance during the dam’s pregnancy.
A congenital lack of kidney tissue.
Failure or suppression of the cellular immune mechanism. This may occur in e.g. human brucellosis, and in other chronic diseases. Anti-anergic treatment with levamisole has been found successful in some patients. (R. D. Thorne, Veterinary Record, 101, 27.) (See also IMMUNOSUPPRESSION.)
The presence of an irregular number of chromosomes (not an exact multiple of the haploid number). It may arise through faulty cell division.
A synonym for THIAMIN.
A dilatation of an artery (or sometimes of a vein or the heart) following a weakening of its walls. The result is a pulsating sac which is liable to rupture.
Aneurysms occur in the abdomen, chest and brain, and may result from a congenital weakness of the blood vessel, from disease of its lining cells, from injury, etc.
Causes Sudden and violent muscular efforts are regarded as the chief factors in the production of aneurysms, and as would be expected, the horse is more subject to this trouble than any of the other domesticated animals.
‘Verminous aneurysm’ is a misnomer for verminous arteritis of horses caused by immature strongyle worms. (See EQUINE VERMINOUS ARTERITIS.)
A dairy breed originally from Schleswig-Holstein mentioned first in the 1600s. They are red in colour and a founding breed within the DANISH RED. The 305-day lactation produces 7,579 kg (16,700 lb), at 4.8 per cent butterfat.
A method of treating a tumour by depriving it of its blood supply.
A radiographic technique which enables the blood-flow to and from an organ to be visualised after injection of a contrast medium.
A TUMOUR composed of a large number of blood vessels. They are common in the livers of cattle. (See also HAEMANGIOMA.)
(See HAEMOSARCOMA.)
(See HEARTWORM.)
Inflammation of a blood vessel, lymph vessel, or bile duct.
An old name for WARTS.
A breed also called Nubian, developed from goats from the Middle East and North Africa. They may be of any colour and have a ‘Roman nose’ and long pendulous ears. They are a dairy breed but can be used for meat. Bucks weigh about 80 kg (175 lb) and does 60 kg (135 lb) with a minimum height at the withers of 90 cm (35 in) for bucks and 75 cm (30 in) for does. The average yield is about 4 kg (9 lb) milk daily with 4.8 per cent butterfat and 3.5 per cent protein.
The name of breeds of rabbit which produce angora wool and goats that produce mohair fibre.
Angora rabbits show a variety of colours; the wool is removed very easily by plucking.
A breed of goats that produce mohair wool. They have a single coat rather than the usual double coat of goats; this grows as ringlets and is shorn twice yearly, usually in January and late summer. It weighs 4 kg to 6 kg (9 lb to 14 lb); that from the male is heavier.
Breed of rabbits that produce angora wool. They show a variety of colours; the wool is removed very easily by plucking.
This is produced from the PELAGE of the Angora rabbit. They show a variety of colours, the wool is removed very easily by plucking. The hair of Angora goats is called mohair.
(See ABERDEEN ANGUS CATTLE.)
A failure of the sweat mechanism. This occurs in horses especially, but also in cattle, imported into tropical countries with humid climates.
At first, affected horses sweat excessively and their breathing is distressed after exercise. Later, sweating occurs only at the mane; the skin becomes scurfy; and breathing becomes more laboured. Heart failure may occur.
A lack of fluid in the blood and a low serum yield. It can result from dehydration or other causes.
An oxide which can combine with water to form an acid.
Containing no water.
A combined agency formed on October 1st 2014 from the ANIMAL HEALTH AND VETERINARY LABORATORIES AGENCY (AHVLA), the Food and Environment Research Agency and Plant Health Agency.
As a guide to animal welfare, see AGGRESSIVENESS; ANAESTHESIA, GENERAL; ANALGESICS; ETHOLOGY; ELECTRIC SHOCK, ‘STRAY VOLTAGE’ AND ELECTROCUTION; HOUSING OF ANIMALS; TRANSPORT STRESS.
This requires that the owner of a boarding establishment shall obtain a licence from the Local Authority, and that this licence must be renewed annually. The applicant has to satisfy the licensing authority on certain personal points, and that the ‘animals will at all times be kept in accommodation suitable as respects construction, size of quarters, number of occupants, exercising facilities, temperature, lighting, ventilation and cleanliness’. The Act also requires that animals boarded ‘will be adequately supplied with suitable food, drink, and bedding material, adequately exercised, and (so far as necessary) visited at suitable intervals’. Isolation facilities and fire precautions are covered by the Act, which empowers the Local Authority to inspect both the boarding establishment and the register which must be kept there. A copy of the licence and its conditions must be suitably displayed.
(See DISEASES OF ANIMALS (WASTE FOOD) ORDER 1973.)
The Regulation prevents the feeding of catering waste to farm animals and enacted legislation of The Animal By-Products Regulation (EC) 1774. 2002 that came into force on May 1st 2003. A UK national ban (SI 2001.1704) had previously come into operation on 24th May 2001 following the onset of the FOOT-AND-MOUTH DISEASE outbreak. This includes the prevention of the feeding of SWILL to pigs. Poultry litter and also compost and anaerobic digestion residues should not be used as bedding for animals.
This is located at the National Centre for Animal Statistics, Westside, Newton, Stocksfield, Northumberland NE43 7TW.
(See CONCENTRATES; DIET AND DIETETICS; RATIONS FOR LIVESTOCK; PROTEINS; POISONING; VITAMINS; ADDITIVES; PET FOODS; also DOGS’ DIET; CAT FOODS, etc.)
This consolidated the Diseases of Animals Acts 1950, 1953 and 1975, 1981. (See also ANIMAL WELFARE ACT 2006).
This was formed from the merger of Animal Health (formerly State Veterinary Service) with the Veterinary Laboratories Agency on 1 April 2011. The address is the Animal Health Corporate Headquarters, Block C3, Government Buildings, Whittington Road, Worcester WR5 2LO. Telephone: 01905 763355; website: http://www.defra.gov.uk. It is now known as the ANIMAL AND PLANT HEALTH AGENCY (APHA). (See VETERINARY INVESTIGATION CENTRES.)
A body created in April 2011 to drive policy for farm animals, equine and companion animal health and welfare. It is composed of stakeholders and 5 DEFRA representatives.
The Act under which prosecutions for cruelty neglect or lack of proper care in the case of vertebrate animals are taken in Scotland. Part 1 updates part of the Animal Health Act 1981 in relation to Scotland.
(See under HEALTH SCHEMES FOR FARM ANIMALS.)
A charity that is one of the world’s leading centres for research into animal health. Its Equine Research Station is renowned for its studies of the physiological and anatomical factors affecting performance, and the small animal centre has particular expertise in eye problems of the dog and cat. AHT research has led to breakthroughs in anaesthesia and in the development of vaccines against equine flu and canine distemper. The address is: Animal Health Trust, PO Box 5, Newmarket, Suffolk CB8 7DW.
(See GRAZING MANAGEMENT; PASTURE MANAGEMENT; HOUSING OF ANIMALS; WATER AND WATERING OF ANIMALS; DIET AND DIETETICS; DAIRY HERD MANAGEMENT; SHEEP BREEDING AND MANAGEMENT; also COWS, PIGS, etc.)
(See VETERINARY NURSES – Professionals who have passed the requisite examinations in small animals or horses under the auspices of the Royal College of Veterinary Surgeons).
(See HOUSING OF ANIMALS.)
This replaced the Cruelty to Animals Act 1876. The 1986 Act makes it illegal to supply animals, other than those purpose-bred in Home-Office-designated breeding establishments, for use in experimental procedures involving dogs, cats, and other animals. The Act requires all laboratories in the UK where animals are used in research to appoint a veterinary surgeon to be responsible for the care and welfare of their experimental animals.
On 1 January 1990 it became illegal to sell or supply pet or stray animals for use in scientific experiments.
The Act also represents the culmination of the efforts of three organisations – the British Veterinary Association (BVA), the Committee for the Reform of Animal Experimentation (CRAE), and the Fund for the Replacement of Animals in Medical Experiments (FRAME) – to reform animal experimentation legislation. The new Act is firmly rooted in BVA/CRAE/FRAME proposals sent to the Home Secretary in 1983, and represents an effective compromise between the welfare needs of animals, the legitimate demands of the public for accountability, and the equally legitimate requirements of medicine, science and commerce.
The legislation gives the Home Secretary the power and the responsibility to judge the scientific merit of the work s/he authorises and for which s/he will be answerable to Parliament.
(See TRANSPORT STRESS.)
The main Act in England and Wales under which prosecutions may be made for cruelty, neglect or lack of proper care to all vertebrate animals. There is a ‘duty of care’ to all owned animal species. The Act stipulates that animals should be provided with a suitable living environment and diet, and requires that animals are allowed to exhibit normal behaviour patterns and should have protection from pain, suffering, injury and disease. There is provision for action to be taken when the circumstances of an animal or animals is unlikely to improve. A person commits an offence if an act or failure to act results in an animal suffering and that it is unnecessary suffering. Subsidiary legislation may differ between England and Wales. (See FARM ANIMAL WELFARE COMMITTEE; ‘FIVE FREEDOMS’ FOR FARM ANIMALS.)
(See WELFARE CODES FOR ANIMALS.)
(See ORIFICES, IMMUNITY AT.)
A negatively charged ion which is attracted to the positive electrode (anode) of the battery. They can combine with CATIONS to make compounds such as acids, alkalis and salts. They are important when producing DIETARY CATION-ANION BALANCE.
The congenital absence, complete or partial, of the iris.
It is incorporated in herbal remedies of dogs and cats, acting as a carminative and mild expectorant.
Inequality between the two limbs.
The condition of a joint in which the movement is restricted by union of the bones or adhesions. (See JOINTS, DISEASES OF.)
The absence of teeth.
Anodynes are pain-relieving drugs.
Anoestrus is the state in the female when no oestrus or ‘season’ is exhibited. It is a state of sexual inactivity. In most mares, for example, anoestrus occurs during the winter months, when daylight is reduced, ambient temperatures are low and, in the wild state, food is scarce. In these circumstances the pituitary gland does not release the gonadotrophins FSH and LF (see HORMONES) so that neither follicles nor corpora lutea develop in the ovaries.
Similar circumstances apply with cattle. Fear, hunger, cold and pain may all result in anoestrus. (See also OESTRUS.)
Absence of eyes: a congenital condition. It is seen unhatched chicks resulting from being in a ‘hot spot’ in the incubator.
The lack of one or both eyes. Also called ANOPHTHALMIA.
The congenital absence of one or both testes.
The lack or loss of appetite. Appetite is mainly physiologically dependent in memory and associations from the sight, small or thought of food. (See APPETITE – Diminished appetite.)
The defective development of bone with a failure to ossify.
The congenital absence of ears.
Absence of ovaries. This is seen in ‘WHITE HEIFER DISEASE’.
Oxygen deficiency. Cerebral anoxia, or a failure in the oxygen supply to the brain, occurs during nitrite and prussic-acid poisoning; in copper deficiency in cattle; and in the thoroughbred ‘barker foal’. Anoxia is a method of slaughter allowed under the Welfare of Animals (Slaughter or Killing) Regulations 1995 (as amended). (See also ANAESTHESIA, GENERAL.)
Drug antagonism occurs when two incompatible medicines are mixed or administered. Bactericidal antibiotics that act on multiplying organisms (e.g. penicillins) may have no effect if used with bacteriostatic antibiotics that prevent multiplication (e.g. tetracyclines).
Before death. An ante-mortem inspection is the name for an examination of the live animal which is used in conjunction with the findings of a post-mortem inspection, or autopsy. Under the Welfare of Animals (Slaughter or Killing) Regulations 1995, ante-mortem inspections are carried out on animals after their arrival at an abattoir and before they are stunned.
Infection of the fetus before birth. Examples of this may occur with the larvae of the dog hookworm, Ancylostoma caninum, and with the larvae of other roundworms. (See Toxocara.) Toxoplasmosis is another example of an infection which may occur before birth.
Ante-partum paralysis is a condition in which the hindquarters of the pregnant animal suddenly become paralysed. It is fairly common in the cow, has been seen in the sheep and goat, but is rare in the mare. It appears from 6 to 25 days before parturition, and is liable to affect animals in almost any condition – those that are well kept as well as others.
Signs The condition suddenly appears without any warning. The pregnant animal is found in the lying position, and is quite unable to regain her feet.
Treatment As a rule, the nearer to the day of parturition that the paralysis appears, the more favourable will be the result. Those cases that lie for 2 or more weeks are very unsatisfactory. The condition usually disappears after parturition has taken place, either almost at once or in 2 or 3 days. As a consequence, treatment should be mainly directed to ensuring that the animal is comfortable, provided with plenty of bedding, is turned over on to the opposite side 3 or 4 times a day if she does not turn herself, and receives a laxative diet so that constipation may not occur. Mashes, green food, and a variety in the food stuffs offered, are indicated. When the paralysis has occurred a considerable time before parturition is due, it is often necessary to produce artificial abortion of the fetus and so relieve the uterus of its heavy encumbrance.
Routine use of an anthelmintic tends to establish resistance to its effects. Resistance to anthelmintics in sheep and goats has become a serious problem in Australia and is increasing in other countries including UK, where livestock are regularly dosed. It is also a problem in horses, although uncommon in cattle. Goats do not acquire age-related resistance to helminths and anthelmintic over-use can rapidly produce resistance. The development of resistance may be discouraged by changing the class of anthelmintic used for each year’s dosing programme. Worming products are labelled with the following codes that identify their chemical type:
1-BZ Benzimidazoles, probenzimodazoles (white)
2-LV Imidazothiazoles, tetrahydropyrimidines (yellow)
3-ML Avermectins, milbemycins (clear)
4-AD Amino-acetonitrile derivatives (orange)
5-SI Spiroindoles (purple)
Products with the same codes should not be used on the same animals in successive seasons. The aim of the veterinary practitioner must be to minimise the use of anthelmintic treatment. Anthelmintics should only be used when it is necessary to prevent clinical disease. In this way the rate of acquiring resistance will be reduced and drug efficacy preserved longer. To do this it is important that the number of worms in REFUGIA is increased. (Worms which are not in the animal and so are not subject to anthelmintic treatment are said to be in refugia.) After treatment there are always some resistant worms that survive. Once resistant worms are in the majority, anthelmintic resistance will rapidly develop. The selective treatment of only animals showing signs of infestation significantly increases the percentage of the worms in refugia.
It is now considered that where sheep, goats and camelids are continually exposed to worms it is beneficial for the animal to retain a few worms. This will not only assist the formation of immunity but also prolong the effectiveness of the available anthelmintics. The selective treatment of only those animals showing signs of worm infestation significantly increases the percentage of the worms in refugia.
Anthelmintics are medicines which are given to expel parasitic worms. There is a large range of substances and formulations from which to choose as wormers. Anthelmintic drugs include abamectin, albendazole, dichlorophen, dichlorvos, doramectin, fenbendazole, haloxon, ivermectin, levamisole, monepantel, moxidectin, nitroxynil, tetramisole, morantel tartrate and thiophanate. Niclosamide, praziquantel, and triclabendazole are used against tapeworms in the dog. (See also DRONCIT.) Fenbendazole and albendazole are broad-spectrum anthelmintics usually effective against inhibited fourth-stage ostertagia larvae in cattle, as are macrocyclic lactones and amino acetonitrile derivatives (Ads or AADs).
Certain criteria apply in the selection of anthelmintics. For example, will the drug in question kill worm eggs? Is it effective against immature worms? Is it effective against adult worms of the economically important species? Does the drug discolour or taint milk? Can it be given to pregnant, or emaciated, animals? In cows, for how long must the milk be discarded after administration?
Methods of dosing include drenching; injection in the feed and ‘pour ons’. (See also WORMS, FARM TREATMENT AGAINST.)
The proprietary name for mepyramine maleate, an antihistamine compound, often applied topically. It is not licensed for veterinary use in the UK.
(See SWEET VERNAL GRASS.)
Anthrax, a NOTIFIABLE DISEASE, is one of the most serious ZOONOSES. It is an acute, usually fatal, infection found in mammals; it is commonest among the herbivora. All cases of unexpected sudden death in cattle must be notified. Any animal that dies suddenly and unexpectedly without an obvious cause should be considered to be an anthrax suspect and investigated as such. In many countries, this sudden death should be reported to the local office of the government veterinary service for investigation. In England, Scotland and Wales this should be the local office of AHVLA, in Northern Ireland the duty veterinarian DARD, and in the Irish Republic, the duty veterinarian in DAFF. In the event of any difficulty making contact with these bodies, the owner/farmer should speak to their veterinary surgeon for advice. The premises concerned will be subject to restrictions and arrangements made for the affected carcase to be destroyed if the investigation does not rule out the suspicion of anthrax in that animal.
Cause The Bacillus anthracis. Under certain adverse circumstances, each rod-shaped bacillus is able to form itself into a spore. The spores of anthrax are hard to destroy. They resist drying for a period of at least 2 years. They are able to live in the soil for 10 years or more and still be capable of infecting animals. Consequently pastures that have been infected by spilled blood from a case that has died are extremely difficult to render safe for stock.
Earthworms may carry the spores from deeper layers of the soil up to the surface. Spores have been found in bone-meal, in blood fertilisers, in wool and hides and in feeds. (See also STREAMS.)
The bacillus itself is a comparatively delicate organism and easily killed by the ordinary disinfectants.
Method of Infection In cattle, infection nearly always occurs by way of the mouth and alimentary system. Either the living organisms or else the spores are taken in on the food or with the drinking water. Flies can spread the disease. Anthrax has been caused through inoculation of vaccine contaminated by spores; sheep should not be inoculated, therefore, in a dusty shed. Unsterilised bone-meal is an important source of infection (not in the UK).
Signs Three forms of the disease are recognised: the peracute, the acute, and the subacute.
Cattle In most peracute cases, the animal is found dead without having shown any noticeable signs beforehand. Acute: a temperature of 41° C to 41.6° C (106° F or 107° F), a thin, rapid pulse, coldness of the ears, feet, and horns, and ‘blood-shot’ eyes and nostrils. After a few hours this picture is followed by one of prostration, unconsciousness, and death. In either of the above types there may have been diarrhoea or dysentery.
In the subacute form, the affected animal may linger for as long as 48 hours, showing nothing more than a very high temperature and laboured respirations. Occasionally cattle may be infected through the skin, when a ‘carbuncle’ follows, similar to that seen in man. Diffuse, painless, doughy swellings are seen in other cases, especially about the neck and the lower part of the chest.
As sudden death of an animal is often wrongly attributed to lightning strike, a farmer should consult a veterinary surgeon (who will carry out a rapid blood test) to make sure that the cause of death is not anthrax – before handling the carcase, cutting into it, moving it, or letting farm dogs, hounds, cats, etc., feed upon it. A blood smear is taken by the veterinary surgeon, stained and examined under the microscope for the presence or absence of the bacterium. If these are absent a carcase can be moved and opened.
Sheep and goats Anthrax in these animals is almost always of the peracute type.
Horses The disease is not always as serious in horses as it is in cattle. Signs depend on the mode of infection. There are two main forms of signs. In one form, due to insect transmission, there is a marked swelling of the throat, neck, and chest. In the second form of equine anthrax, resulting from indigestion, a fit of shivering ushers in the fever. The pulse rate becomes increased, the horse lies and rises again with great frequency; it shows signs of slowly increasing abdominal pain by kicking at its belly, by gazing at its flanks, or by rolling on the ground.
Pigs The disease may follow the feeding of slaughter-house refuse or the flesh of an animal that has died from an unknown disease (which has really been anthrax), or raw bone-meal intended as a fertiliser - all illegal in the UK. There is sometimes swelling of the throat; the intestine may be involved. In this abdominal form the signs may be very vague. Otherwise the pigs are dull, lie a good deal, show a gradually increasing difficulty in respiration, and present in the early stages a swelling of the throat and head which later invades the lower parts of the neck. Recovery is not unknown.
Dogs and cats A localised form, with oedema of the head and neck (similar to that in the pig), is characteristic. Anthrax has also been reported in zoological collections.
Prevention and Treatment In Great Britain, as in most developed countries, anthrax is a NOTIFIABLE DISEASE. Vaccines are not available commercially. In Britain, DEFRA may be contacted for information about emergency supplies of vaccine. Antibiotics, particularly penicillin, if given early enough, may be effective. When cases have occurred check health and, ideally, temperature of in-contact animals daily.
In so far as its prevention is concerned, the important points to remember are (1) disposal of the carcase by efficient and safe means (see DISPOSAL OF CARCASES) and (2) frequent observation of other animals which have been in contact with the dead one; also their isolation if showing a rise in body temperature.
Sodium hypochlorite (or bleaching powder in a hot 10 per cent solution) kills both bacilli and the spores almost instantaneously.
The milk from in-contact animals must be regarded as dangerous until such time as these are considered to be out of danger. The law forbids anyone who is not authorised to cut an anthrax carcase for any purpose whatsoever. Cases of death from this procedure are by no means unknown, and illness following the dressing of a carcase must always be considered suspicious of anthrax until the contrary has been established. The need for reporting illness to the medical authorities by all persons whose work brings them into contact with carcases of animals cannot be too strongly stressed.
Anthrax in human patients Anthrax is now very rare in humans, with only a handful of cases having been notified in recent years. It may take the form of an inflamed pustule accompanied by fever and prostration, if infection is via the skin – e.g. through a cut. In cases of internal infection, by inhaling or swallowing the spores, pneumonia or intestinal ulceration usually cause death within 2 days if not treated promptly. The infection is more often contracted by workers handling infected meat or meat and bone-meal than by farmers. Any person who has handled an anthrax carcase should seek medical advice.
This order requires the person in charge of an animal or carcase suspected of being infected with anthrax, which includes any animal that has died suddenly without obvious cause to notify the local office of Animal Health (AHVLA), which will organise a veterinary investigation. In the event of there being difficulty in contacting Animal Health, the farmer should contact his DEFRA contract Official Veterinarian. If the investigation shows the presence of anthrax, the premises may be declared an infected place. The local authority has the responsibility of disposing of the carcase by incineration or other suitable method. The Veterinary Officer supervises cleansing, disinfection, vaccination, etc. If the owner refuses to carry out these procedures, the Veterinary Officer can have them carried out and recover the cost from the owner. The Anthrax (Amendment) Order 1996 enables the veterinary inspector to require the incineration of things that have been in contact with or used by an infected animal.
Diseases transmissible from man to lower animals. Such diseases include: tuberculosis, infestation with the beef tapeworm; influenza in pigs and birds. (Compare ZOONOSES.)
A chemical compound derived from living organisms or synthesised from biological material capable, in small concentration, of inhibiting the life process of micro-organisms. To be useful in medicine, an antibiotic must (1) have powerful action in the body against 1 or more types of bacteria; (2) have specific action; (3) have low toxicity for tissues; (4) be active in the presence of body fluids; (5) not be destroyed by tissue enzymes such as trypsin; (6) be stable; (7) be not too rapidly excreted; (8) preferably not give rise to resistant strains of organisms. (Professor F. Alexander.)
Antibiotics are much used in veterinary medicine to overcome certain infections, and they have been of notable service, for instance, in the control of certain forms of mastitis in dairy cattle, in the avoidance of septicaemia following badly infected wounds, deep-seated abscesses, peritonitis, etc. Abdominal and other surgery has been rendered safer by the use of antibiotics. The prophylactic use of antibiotics has been an important factor in the intensive production of livestock and poultry. They must not, however, be used indiscriminately, be regarded as a panacea, or be given in too low a dosage and they cannot be used for growth promotion in UK or EU. It is unwise to use antibiotics of the tetracycline group in either pregnant or very young animals owing to the adverse effects upon bone and teeth which may result.
Certain antibiotics are effective GROWTH PROMOTERS. Their widespread use has in part contributed to the development of resistance to antibiotics, and it is vital to realise that antibiotic use must be considered as part of the overall health and welfare plan, and not a substitute for good husbandry. An exception is in the use of intramammary antibiotic infusions when milking cows are dried off; it is the only known way of keeping subclinical infection of the udder under control. These infusions are also a rare example of where the use of two or more antibiotics in the same preparation can be more effective than just one.
Selection of Antibiotic It is often necessary to begin antibiotic therapy before the results of biological examinations are available, and therapy must depend on the clinical features. However, the taking of material for culture and carrying out sensitivity tests are most important procedures. Another factor in veterinary practice is the cost of the drug. However, minimising dose can lead to increasing the possibility of resistance.
Only in a very few instances are mixtures of antibiotics superior to a single drug. In those cases in which more than one antibiotic is required, the full dose of each of the individual antibiotics should be given so as to exceed the MINIMUM INHIBITORY CONCENTRATION. Combined antibiotic therapy does not improve the outlook in chronic urinary infections or, indeed, many chronic infections. Mixtures of antibiotics have been most successful when used in local applications or in infections of the alimentary canal. (See ADDITIVES, and under MILK.) Some of the most widely-used group and individual antibiotics in veterinary medicine are: BENZYLPENICILLIN, procaine penicillin (under PROCAINE HYDROCHLORIDE), AMPICILLIN, AMOXYCILLIN, STREPTOMYCIN, NEOMYCIN, TETRACYCLINES, CHLORAMPHENICOL, GRISEOFULVIN, CHLORAMPHENICOL, ERYTHROMYCIN, GRISEOFULVIN, CEPHALOSPORINS, FLUOROQUINOLONES. (See also CEPHALOSPORIN ANTIBIOTICS, TIAMULIN, SALINOMYCIN; and below.)
For advice on selection of antibiotics for treatment, see The Veterinary Formulary (RPSGB/BVA).
A 2012 survey of Irish cattle practitioners in showed that previous experience with a particular antibiotic was a major consideration when prescribing. Non-clinical issues concerning stresses and perceived or actual pressures on the veterinary surgeon had an influence in most cases.
The widespread use of antibiotics has become associated with the development of resistance to their effects. Bacteria can become drug-resistant in one of two ways. Chromosomal resistance develops through mutation and is probably rare. Bacteria which achieve this kind of resistance are unable to transfer it to other bacteria, but pass it on to their own future generations through the ordinary process of cell division.
The second method is transmissible drug resistance (TDR). This is achieved by means of PLASMIDS.
Many bacteria carry, in their cytoplasm, resistance or R factors. These are pieces of DNA which include genes coding for resistance to antibiotics and other genes which facilitate the transit of the R factor to other bacteria. Both groups of genes are carried on plasmids.
A GRAM-NEGATIVE bacterium which possesses an R factor is able to conjugate with other Gram-negative bacteria. This involves intimate contact through a protoplasmic bridge called a sex pilus. When this occurs a duplicate of the R factor is transmitted to the second, recipient, cell, which thereby acquires both the drug resistance and the ability to transmit it to other bacteria.
Inside the gut of an animal being dosed with an antibiotic, these resistant bacteria survive and multiply at the expense of the antibiotic-sensitive bacteria. Cross-infection can then bring about a similar situation in other animals.
The persistence of TDR in the animal gut has been related to the pattern of antibiotic usage. Continuous low-level administration of antibiotics has been shown to increase the incidence of resistant organisms. The emergence of resistant strains of salmonella in calves receiving in-feed antibiotics has been of concern. As long ago as 1972, a MAFF study of 2166 strains of salmonella isolated from farm animals found that 90 per cent were resistant to streptomycin.
There has been concern that the use of antibiotics as growth promoters could encourage development of resistant organisms. Consequently, antibiotics used in this way were to be selected from those not used therapeutically in animals or humans. They were subsequently banned from such use.
On the other hand, specific full-dose treatments for acute conditions are less likely to create persistent resistance problems. For example, administration in dairy herds of an antibiotic via the teat, over short periods of time, or as a preventive during the dry period, seems to have had little effect on drug-resistance in the herd.
(See PENICILLIN, SENSITIVITY TO; NEOMYCIN; CHLORAMPHENICOL; TETRACYCLINES; TYLOSIN.)
Antibiotic feed supplements are permitted for treatment purposes only. Their use as growth promoters has been banned in the EU since January 2006. (See under ADDITIVES.)
A substance in the blood serum or other body fluids formed to exert a specific restrictive or destructive action on bacteria, their toxins, viruses, or any foreign protein.
Antibodies are not produced, like hormones, by a single organ, the blood then distributing them throughout the body. Antibody production has been shown to occur in lymph nodes close to the site of introduction of an antigen, in the skin, fat, and voluntary muscle, and locally in infected tissues.
Chemically, antibodies (belonging to a group of proteins called immunoglobulins) are protein molecules of complex structure. In the IMMUNE RESPONSE, antibody and antigen molecules combine together in what is called a complex. These complexes are removed from the body by the RETICULO-ENDOTHELIAL SYSTEM. Agglutination of bacteria and precipitation of soluble protein antigens both occur following combination of antibody and antigen molecules, and are made use of in laboratory tests.
Antibodies are not always protective; some join mast cells and eosinophils after exposure to the specific antigen resulting in the release of histamine, as happens in ALLERGY. (See also REAGINIC ANTIBODIES.)
Agents which inhibit clotting of the blood. They are used to prepare blood for transfusion or for various tests. Many substances with anticoagulant properties are commonly used as rodenticides and can result in accidental poisoning of dogs and other animals. They include WARFARIN, dicoumarol and heparin. They are used in the treatment of coronary thrombosis in humans.
Substances secreted by leeches and hookworms in order to prevent clotting of the blood, which they suck.
A triplet of nucleotides in transfer RNA; it is complementary to the CODON in messenger DNA which specifies the amino acid
Drugs used in the treatment of epilepsy to control seizures. (See also PHENYTOIN SODIUM.)
Also called VASOPRESSIN, ADH is secreted by the posterior lobe of the PITUITARY GLAND. It stimulates absorption of water by the renal tubules, thus concentrating the urine. A deficiency of ADH leads to DIABETES INSIPIDUS. Avian diuretic hormone is ARGININE VASOTOCIN
Antidotes neutralise the effects of poisons either (a) by changing the poisons into relatively harmless substances through some chemical action, or (b) by setting up an action in the body opposite to that of the poison.
First-aid and other antidotes are given under the various poisons – see POISONING.
A medicine which prevents vomiting and can be used in motion sickness.
A substance that inhibits the action of an enzyme. Non-micronised soya contains an anti-pepsin substance.
Antifreeze is ethylene glycol, and cats and dogs are attracted by its sweet taste. The signs are depression, ataxia and coma, sometimes with vomiting and convulsions. Ethylene glycol is oxidised in the body to oxalic acid, the actual toxic agent, and crystals of calcium oxalate may be found on post-mortem examination in the kidneys and blood vessels of the brain. Treatment attempts to swamp the enzyme systems which bring about this oxidation by offering ethanol as an alternative substrate. This is achieved by the intravenous administration of 20 per cent ethanol and 5 per cent sodium bicarbonate to correct acidosis; vodka (40 per cent alcohol) is a readily available source of alcohol. An alcohol dehydrogenase inhibitor, 4-methylpyrazole, has been reported effective in cases where azotaemia (nitrogen in the blood caused by toxic kidney failure) has not occurred. In early cases use emetics; absorbents do not help.
A substance which causes the formation of antibodies. (See IMMUNE RESPONSE; VACCINE; H-Y ANTIGEN.)
An antigenetic change caused by mutations of genes which may change the infective and antibody characteristics of a virus.
An antiserum against the globulin part of the serum, and used in the indirect fluorescent antibody test and COOMBS TEST.
The action of histamine is dependent on biological receptors which are designated as H1 and H2 depending on the activity of histamine at each site. Antihistamines are drugs which neutralise the effects of histamine in excess in the tissues and are said to act either by (1) antagonising the action of histamine on H1 receptors (e.g. diphenhydramine hydrochloride, mepyramine maleate, chlorpheniramine maleate and promethazine hydrochloride used to treat allergic disorders, laminitis, urticaria, light sensitisation, anaphylaxis) or (2) on H2 receptors (e.g. cimetidine and ranitide) used to treat travel sickness involving dogs and cats). Not all are licensed for use in all species and they should not be used except under professional advice. (See HISTAMINE.)
True antibodies formed consequent upon the injection of hormones.
Antiketogenic is the term applied to foods and remedies which prevent or decrease the formation of ketones.
Antimony (Hb) is a metallic element belonging to the class of heavy metals. Antimony salts are little used now in veterinary medicine than formerly, less toxic substitutes being preferable.
Uses Tartar emetic, the double tartrate of antimony and potassium, was used for intravenous injection against certain trypanosomes and other protozoon parasites. (See ANTIDOTES.)
Destroys fungi.
A substance that, in small amounts, can inhibit the oxidation of other compounds. They are used in feeds to prevent rancidity of polyunsaturated fats. In the body they prevent cellular damage such as muscular dystrophy. They are present in several forms including vitamin E. Excessive antioxidant supplementation may actually damage cellular function. (See VITAMINS – Vitamin E.)
(See POULTICES AND FOMENTATIONS.)
Antipyretics are drugs used to reduce body temperature during fevers (pyrexias).
Agents which inhibit the growth of micro-organisms, and are suitable for application to wounds or the unbroken skin. Preparations designed to kill organisms are properly called ‘disinfectants’ or ‘germicides’. Many substances may be either antiseptic or disinfectant according to the strength used.
Very strong antiseptic or disinfectant solutions should not be used for wounds because of the destruction of cells they cause. The dead cells may then retard healing, and in some cases are later cast off as a slough.
The following are among substances used, suitably diluted or in formulation as creams or ointments, as animal antiseptics.
Chlorine compounds in several different forms are used for cleansing wounds from the presence of organisms. Among the class may be mentioned eusol, eupad, ‘TCP’*, etc. They include sodium hypochlorite and chloramines, both also used as disinfectants.
Quaternary ammonium compounds (see under this heading) are widely used in dairy hygiene. They include cetrimide and benzalkonium chloride.
Dettol*, solution of Chloroxylenol, BP Powerful bactericide of relatively low toxicity. Useful for skin cleansing, obstetrical work, and disinfecting premises. The bactericidal action is reduced in the presence of blood or serum.
Crystal violet in 1 per cent solution has in the past formed a useful antiseptic for infected wounds, burns, fungal skin diseases, and chronic ulcers. Similarly, gentian violet.
Common salt (a teaspoonful to a pint of boiled water) is useful as a wound-cleansing agent and is usually easily obtainable when other antiseptics may be lacking.
Iodoform* is a powerful, poisonous but soothing antiseptic formerly often used for dusting on to wounds as a powder with boric acid.
Iodine* in an alcoholic solution is more penetrating and irritant, especially to delicate skins. For use on the unbroken skin only.
Alcohol is a very powerful antiseptic chiefly used for removing grease and septic matter from the hands of the surgeon and the skin of the patient.
Hydrogen peroxide (see under this heading).
* Their injudicious use could lead to toxicity in cats, so for them other antiseptics are preferable.
A serum for use against a specific condition is produced by inoculating a susceptible animal with a sub-lethal dose of the causal agent or antigen and gradually increasing the dosage until very large amounts are administered. The animal develops in its blood serum an antibody which can be made use of to confer a temporary protection in other animals against the bacterium or toxin. Few antiserum preparations are now used, except Tetanus Antitoxin.
The use of antiserum alone confers a temporary immunity, and in most cases this probably does not protect for longer than from 10 days to a maximum of about 21 days. Antisera are used in the treatment of existing disease, and also as a means of protecting animals exposed to infection. (See BLACK-QUARTER; RABIES; TETANUS; JAUNDICE (Leptospiral) for examples of diseases where serum therapy may be useful.) (See also ANAPHYLACTIC SHOCK; IMMUNITY.)
Substances which reduce salivation, e.g. atropine.
Antispasmodics are drugs which diminish spasm causing colic or ‘cramp’. They mostly act upon the muscular tissues, causing them to relax, or soothing nerves which control the muscles involved. Antispasmodic drugs include ATROPINE, propan-theline, cisapride and hyoscine (in Buscopan Compositum)
A hyper-immune serum used against TETANUS. Nowadays, the vaccine is preferred or a combination of the antitoxin and vaccine is used.
Antitoxins (antitoxic sera) are substances which neutralise the harmful effects of a toxin.
Antivenin is a substance produced by the injection of snake venom into animals in small but increasing doses. In course of time the animal becomes immune to the particular venom injected, and the antivenin prepared from its serum is highly effective in neutralising venom injected by the bite of a snake of the same species. To be of any use it must be administered within about one hour of the snake bite.
Antidote to the venom of adders in the UK; used for the treatment of domestic animals bitten by adders. There are many other antivenoms used to treat bites by specific snakes throughout the world.
A substance used against viruses. (See also INTERFERON.)
These counteract vitamins. Thiaminase is present in some fish but it is destroyed by cooking. (See AVIDIN.)
An agent which inhibits fermentation.
Antlers are grown by stags (male deer), and male and female reindeer, complete with blood supply to the velvet (the soft hairy outer layer) each year. A prime red deer stag will grow 4 kg in 3 months (May to July in the UK). Its diet must provide 600 g calcium, 300 g phosphorus and 12 g magnesium to achieve this – almost twice as much as a hind in full lactation needs.
A synthetic drug used in the control of trypanosomiasis.
Ants are of veterinary interest as intermediate hosts of the liver fluke Dicrocoelium dendriticum. This fluke, which is smaller than Fasciola hepatica, the common fluke, is found in sheep, goats, cattle, deer, hares, rabbits, pigs, dogs, donkeys and, occasionally, man. In the British Isles, the fluke occurs only (it is believed) in the islands off the Scottish mainland and South West England.
The fluke’s eggs are swallowed by a land-snail of the genus Helicella. From the snail, cercariae periodically escape and slimy clumps of them are eaten by ants (Formica fusca in the USA). Grazing animals, swallowing ants with the grass, then become infested.
Ants also act as the intermediate host of a tapeworm of the fowl, guinea-fowl and pigeon, Raillietina tetragona.
Pharaoh’s ants have been shown to be of considerable medical importance. They are much smaller than the common black ant; the worker, brownish-orange in colour, measures only 2 mm in length. They are a tropical species and in a temperate climate survive where there is central heating or its equivalent.
Their nests have been found behind tiles, in light fittings, fuse-boxes, and even in hospital operating theatres! Small nests are sometimes found between the folds of sheets and towels coming from laundries.
These ants eat meat, and also sweet foods. In their quest for water they visit sinks, drains, lavatories, etc. and can therefore contaminate food. They also, apparently, feed on the discharges from infected wounds.
Pharaoh’s ants constitute a public health danger since they can carry disease-producing bacteria. In the isolation unit of a school of veterinary medicine they ruined one experiment by carrying infection from known infected animals to the uninfected ‘controls’.
Fire ants (Soleropsis invicta) have become established in the southeastern states of the USA. They are very aggressive and masses of them will attack and eat quail fledglings, for example, and unweaned rabbits. People camping out near fire-ant colonies have also been attacked; the ant ‘venom’ causes blurred vision, loss of consciousness and sometimes convulsions.
Alphanaphthylthiourea, used to kill rodents. One gram may prove fatal to a 9 to 11 kg (20 to 25 lb) dog. The poison gives rise to oedema of the lungs. (See also THIOUREA.) Antu is banned in the UK.
Amphibians having no tails in the adult stage – frogs and toads. Also known as Salientia.
Anuria is a condition in which little or no URINE is excreted or voided for some time. (See also KIDNEYS.)
The opening which terminates the alimentary canal. In health it is kept closed by the sphincter ani, a ring of muscle fibres about 2.5 cm (1 in) thick in the horse, which is kept in a state of constant contraction by certain special nerve fibres situated in the spinal cord. If this ring fails to relax, constipation may result, while in some forms of paralysis the muscle becomes unable to retain the faeces. Imperforate anus is a defect in which an animal is born without any such opening – in effect, the absence of an anus. Absence of an anus is ATRESIA ANI.
There are two of these in the dog, situated below and to each side of the anus. They produce a malodorous fluid which possibly acts as a lubricant to aid defaecation or as a means of territorial marking. Each gland has a duct opening just inside the anus. These ducts may become blocked by a grass seed or other foreign body, so that the secretions cannot escape and the glands swell; but more commonly there is infection. Irritation or pain then results. It may be necessary to manually express the glands to relieve the blockage, or to remove them surgically.
Signs include yelping on sitting down, and tail-chasing; more commonly the dog drags itself along the ground (‘scooting, skating, tobogganing’) or licks its hindquarters in a effort to obtain relief.
Perianal fistulae may be due to a number of causes including rupture of the anal sac, inflammation or ulceration. Except in mild cases, the condition may be difficult to treat, surgically or otherwise.
Signs include pain on defaecation and a bad smell. German shepherd dogs are said to be susceptible to the condition.
Perianal furunculosis is sometimes a recurring problem in dogs. Surgical removal of the anal sacs has been recommended to prevent recurrence. (See FURUNCULOSIS.)
In dogs, anxiety may be shown by the animal looking around repeatedly and smacking its lips. This is often seen at veterinary surgeries.
Psychotropic drugs used to treat emotional upsets such as anxiety and depression.
The principal artery of the body. It leaves the base of the left ventricle and curves upwards and backwards, giving off branches to the head and neck and forelimbs. About the level of the 8th or 9th thoracic vertebra it reaches the lower surface of the spinal column, and from there it runs back into the abdominal cavity between the lungs, piercing the diaphragm. It ends about the 5th lumbar vertebra by dividing into the two internal iliacs and the middle sacral arteries. The internal iliacs supply the 2 hind-limbs and the muscles of the pelvis. At its commencement the aorta is about 1.5 inches (3.75 cm) in diameter in the horse, and from there it gradually tapers as large branches leave it. It is customary to divide the aorta into thoracic aorta and abdominal aorta. (See ARTERIES; ANEURYSM.)
This follows degenerative changes in the aorta, and is a not uncommon cause of death of male turkeys aged between 5 and 22 weeks. It was first reported in the USA and Canada. In Britain most cases occur between July and October, the birds being found dead. The condition has also been reported in ostriches and in mammals including horses.
A condition in which the flow of blood from the heart into the aorta is obstructed. It may result from a congenital malformation of the heart valves or an obstruction in the aorta itself. It may be an inherited condition in Boxers, Bulldogs, German shepherd dogs and Newfoundlands. It has also been seen in cats.
Signs may include dyspnoea or congestive heart failure. (See STENOSIS.)
(See ASSOCIATION OF PET BEHAVIOUR COUNSELLORS.)
(See ASSOCIATION OF PET DOG TRAINERS.)
These are classed as higher PRIMATES and are the most closely related to man and therefore they are susceptible to many human diseases. Those dealing with these animals should also consult Black’s Medical Dictionary.
(See ANIMAL AND PLANT HEALTH AGENCY.)
Inability, or refusal, to eat.
A congenital absence of a digit or of one or more phalanges.
Defective development or complete absence of a tissue or organ.
Relating to aplasia, the congenital absence of an organ. In aplastic anaemia, there is defective development or a cessation of regeneration of the red cells, etc. (See ANAEMIA.)
Apnoea means not breathing. Aquatic animals such as seals, ducks and penguins display ‘diving apnoea’ – they hold their breath while under the water.
A gland which sheds some of its cellular content along with its true secretion.
A congenital absence of one or more feet.
A derivative of morphine which has a marked emetic action in the dog, and is used in that animal to induce vomiting when some poisonous or otherwise objectionable material has been taken into the stomach.
Aponeurosis is a sheet of tendinous tissue providing an insertion or attachment for muscles, which is sometimes itself attached to a bone, and sometimes is merely a method of attaching one muscle to another.
Apoproteins are involved in the transport of LIPIDS throughout the body. Apoproteins are produced by cells in the liver or intestine. (See also LIPOPROTEIN.)
A degenerative process of cells involving coagulative necrosis and shrinkage.
The Appaloosa Horse Society of America and the British Spotted Horse Society are concerned with the breeding of this horse, which has some Arab blood and is characterised by a silky white coat with black (or chocolate-coloured) spots which can be felt with the finger.
Inflammation of the appendix; it occurs in rabbits with severe intestinal coccidiosis.
A rudimentary part of the small intestine in primates. In the adult rabbit it is 15 cm long and is found at the distal end of the caecum.
Pica (depraved appetite) A mineral or vitamin deficiency may account for some cases of animals eating rubbish such as coal, cinders, soil, plaster, stones, faeces, etc. Pica is often associated also with pregnancy, alimentary problems, and is an important sign of rabies in dogs. It may result from worm infections.
In cats pica is a sign of anaemia. They will lick concrete or eat cat litter.
Excessive appetite (Polyphagia) may be a sign of dyspepsia or diabetes, of internal parasites, of tuberculosis, of listeriosis, or of the early stages of cancer.
Diminished appetite Anorexia, or a diminished appetite, is a sign usually present in many problems including infections, especially with fever, and most forms of dyspepsia, in gastritis and enteritis, in many fevers, and in abnormal conditions of the throat and the mouth, when the act of swallowing is difficult or painful. In other cases the appetite is in abeyance for no apparent reason. It can indicate that an animal has overeaten, and a rest from eating may be all that is needed. (See NURSING OF SICK ANIMALS; MINERALS; VITAMINS.)
An aminoglycoside antibiotic with activity against Bordetella bronchiseptica, Campylobacter coli, Klebsiella spp., Salmonella spp., Proteus spp., Pseudomonas aeruginosa, Shigella sonnei, Brachyspira spp., and Mycoplasma hyopneumoniae. It can be given orally or intramuscularly and is used in calves, pigs and poultry.
A congenital contraction of the muscles of the hand or feet, fore and hind limbs.
Imperforation or absence of the anus.
Featherless tracts found normally on birds. An absence of feathers under the crest of the head is a normal phenomenon in cockatoos and cockatiels, and many species of bird have normal featherless tracts or apterygia over the neck and under the wings.
A congenital defect in which part or all of a lung is absent.
A fetus without feet.
Means not exhibiting a fever.
(See FISH-FARMING.)
Production of fish foods is highly specialised because the feed is distributed in water, with the danger of soluble constituents dissolving.
The aqueduct of Sylvius (cerebral aqueduct) connects the 3rd and 4th ventricles of the brain, and conveys cerebrospinal fluid.
(See EYE - CONTENTS OF THE EYEBALL.)
Arab horses originated from the Middle East. They are light horses, normally between 14.1 to 15.1 HANDS (1.41 m to 1.51 m) high. They are normally grey, chestnut or bay; black animals are rare. Piebald and skewbald animals are not permitted. They have pretty, small, dish-shaped heads. They make excellent endurance horses and are also used for racing. The foal can suffer from inherited SEVERE COMBINED IMMUNODEFICIENCY; it develops respiratory problems after the maternal immunity has worn off and will eventually die.
A fatty acid which can be synthesised by most mammals and birds from linoleic or linolenic acid. This is not the case in felidae, which require arachidonic acid in their diets. It is necessary for prostaglandin formation. (See EICOSANOIDS, OMEGA-3 FATTY ACIDS.)
The class of Arthropoda to which belong the mange mites, ticks and spiders.
Arachnoid membrane is one of the membranes covering the brain and spinal cord. (See BRAIN.) Arachnoiditis is inflammation of this membrane.
This breed originated in Chile. They have feather tufts near their ears and no tail. There are of various colours including white, black and black with red breasts. They lay blue shelled eggs.
This is an abbreviation for arthropod-borne viruses. They are responsible for diseases (such as louping-ill, equine encephalitis and yellow fever) transmitted by ticks, insects, etc. They are known as Togaviruses. (See VIRUSES table.)
The former Agricultural Research Council, under whose control a number of UK veterinary research institutes functioned. Founded in 1931, it was renamed the Agricultural and Food Research Council (AFRC) in 1983, and was ultimately superseded by the Biotechnology and Biological Sciences Research Council (BBSRC) in 1994.
The current name for a common bacterium of most species which causes pus formation and abscesses. It was formerly called Corynebacterium pyogenes and then Actinomyces pyogenes. (See ACTINOMYCOSIS.)
Areolar connective tissue is loose in character and occurs in the body wherever a cushioning effect, with flexibility, is needed, e.g. between skin and muscle, and surrounding blood vessels.
An essential amino acid required for optimal growth, stimulating growth hormone release and acting as a vehicle for nitrogen transport, storage and excretion. It is important in the formation of collagen, maintaining bone, cartilage and connective tissue during growth and in repair. It is involved in a healthy immune system, spermatogenesis and maintaining memory.
Avian antidiuretic hormone and the natural reptilian oxytocin (See EGG-BOUND; DYSTOKIA.)
A crustacean parasite of freshwater fish which can cause ulceration, poor growth and transmit spring viraemia of carp. These fish lice can be removed by bathing affected fish briefly in saline.
A cardiac deviation of the heart to the right.
In turkeys it was reported for the first time in the UK in 1968. The infection, mainly of birds, is caused by the Arizona group of the entero-bacteriaceae – closely related to the salmonellae and the coliform group. Young birds can be infected by contact or through the egg. Nervous signs and eye lesions are characteristic in birds surviving the initial acute illness.
Over 300 antigenically distinct serotypes of Arizona have been identified. One at least appears to be host-adapted to sheep, and has been recovered from scouring sheep, from ewes which died in pregnancy and from aborted fetuses. Food-poisoning in man and diarrhoea in monkeys have been attributed to Arizona infection.
Arrhythmia means that the heartbeat is not occurring regularly, or that a beat is being periodically missed. It may be only temporary and of little importance; on the other hand it may be a sign of some form of cardiac disease.
One of the organic compounds of arsenic which has been used as a growth supplement for pigs and poultry; now no longer used in the EU.
It should not be given within 10 days of slaughter, nor should the recommended dosage rate be exceeded, as residues – especially in the liver – may prove harmful if consumed. The permitted maximum of arsenic in liver is 1 part per million. In a random survey (1969), 4 of 93 pig livers contained from 1.2 to 3.5 ppm of arsenic, hence the ban.
Blindness, a staggering gait, twisting of the neck, progressive weakness and paralysis are signs of chronic poisoning with arsanilic acid in the pig.
Arsenic (As) is a metal, but the term is commonly used to refer to arsenious acid. It has two forms: the trivalent, which is toxic; and the pentavalent (found in most organic compounds of arsenic), which is not. Arsenic is found in Scheele’s green and emerald green – the two arsenites of copper; Orpiment or King’s yellow, and Realgar – sulphides of arsenic; Fowler’s solution (liquor arsenicalis, BP), which contains arsenic trioxide. It used to be used in older varieties of sheep-dip, rat-poisons, fly-papers, and even wallpapers.
Uses Previously arsenic was used in some compound animal feeds in order to improve growth rate and to prevent histomoniasis (blackhead in turkeys). The disposal of dung containing arsenic residues causes problems: small doses over a long period may give rise to cancer. (See also ARSANILIC ACID.)
Arsenic is an irritant poison producing in all animals gastroenteritis. The rapidity of its action depends on the amount that is taken, on the solubility of the compound, on the presence or otherwise of food in the digestive system, and on the susceptibility of the animal.
Signs include violent purging, severe colic, straining, a staggering gait, coldness of the extremities of the body, unconsciousness, and convulsions. When the poisoning is the result of the taking of small doses for a considerable period, cumulative signs are observed. These include an unthrifty condition of the body generally, swelling of the joints, indigestion, constant or intermittent diarrhoea, often with a fetid odour, thirst, emaciation, and distressed breathing and heart action on moderate exercise.
Causes
Cattle have died after straying into a field of potatoes sprayed with arsenites to destroy the haulm. In some countries others have died following the application to their backs of an arsenical dressing, and of the use of arsenic-contaminated, old bins for feeding purposes.
Sheep Probably most cases of arsenic poisoning in sheep occurred from the use of arsenical dips before other compounds were introduced. The source of this poisoning is in many cases the herbage of the pastures which becomes contaminated either from the drippings from the wool of the sheep, or from the washing of the dip out of the fleece by a shower of rain on the second or third day after the dipping. Absorption through wounds or laceration of the skin may result in arsenic poisoning, and when dips are made up too strong, absorption into the system may also occur. The obvious precautions, apart from care of the actual dipping, are to ensure that the sheep are kept in the draining pens long enough to ensure that their fleeces are reasonably dry (some 15 to 20 minutes) and subsequently are not allowed to remain for long thickly concentrated in small fields or paddocks. Where double dipping is carried out, the second immersion in an arsenic dip must be at half-strength.
Dogs and cats are particularly susceptible to poisoning by arsenic. The signs are nausea, vomiting, abdominal pain, dark fluid evacuations and death, preceded by convulsions.
Antidotes Sodium thiosulphate is a better antidote than ferric hydroxide, and a solution can be given intravenously. (See also DIPS AND DIPPING.)
The arteries carry oxygenated blood away from the heart; that is, blood which has recently been circulating in the lungs, has absorbed oxygen from the inspired air, and has become scarlet in colour. The pulmonary artery is the exception; venous blood of a purple colour which has been circulating in the body and has been returned to the heart, to be sent to the lungs for oxygenation.
The arterial system begins at the left ventricle of the heart with the AORTA. This is the largest artery of the body. It divides and subdivides until the final branches end in the capillaries which ramify throughout all the body tissues except cornea, hair, horn, teeth, scales and feathers. The larger of these branches are called arteries, the smaller ones are arterioles, and these end in the capillaries. The capillaries pervade the tissues like the pores of a sponge, and bathe the cells of the body in arterial blood. The blood is collected by the venous system and carried back to the heart.
Structure Mammalian arteries are highly elastic tubes which are capable of great dilatation with each pulsation of the heart – a dilatation which is of considerable importance in the circulation of the blood. (See CIRCULATION OF BLOOD.) Their walls are composed of three coats: (1) adventitious coat, consisting of ordinary strong fibrous tissue on the outside; (2) middle coat, composed of muscle fibres and elastic fibres, in separate layers in the great arteries; (3) inner coat or intima, consisting of a layer of yellow elastic tissue on whose innermost surface rests a single continuous layer of smooth, plate-like endothelial cells, within which flows the bloodstream. The walls of the larger arteries have the muscles of their middle coat replaced to a great extent by elastic fibres so that they are capable of much distension. When an artery is cut across, its muscular coat instantly shrinks, drawing the cut end within the fibrous sheath which surrounds all arteries, and bunching it up so that only a comparatively small hole is left for the escape of blood. This, in a normal case, soon becomes filled up with the blood clot which is Nature’s method of checking haemorrhage (see BLEEDING).
The proportion of elastic to muscular tissue is much more variable in avian arteries, as between different species and distances from the heart and as the bird ages.
These include:
Arteritis during specific viral diseases such as African swine fever, equine viral arteritis, canine viral hepatitis, etc.
Chronic inflammation is a process of thickening of the arterial wall and subsequent degenerative changes, resulting in an abnormal rigidity of the tube and hindrance to the circulation.
Degenerative changes include atheroma – thickening and degeneration of the lining of the artery. Degeneration occurs in the arteries of pigs, especially, during the course of several diseases. Examples are haemorrhagic gastritis and Herztod disease.
Thrombosis This includes aortic-iliac THROMBOSIS, and femoral thrombosis in dogs and cats. (See also PARAPLEGIA.)
Embolism (see main entry)
Aneurysm (see main entry)
Equine verminous arteritis (see main entry)
Heartworms (see main entry)
Aortic rupture in turkeys (see main entry)
Inflammation of a joint. A common disease of all farm and pet animals. (See also JOINTS, DISEASES OF.)
Causes include trauma, rheumatism, a mineral deficiency, and FLUOROSIS. Infections which cause arthritis include BRUCELLOSIS, TUBERCULOSIS and SWINE ERYSIPELAS. (See also SYNOVITIS; BURSITIS; JOINT-ILL.)
occurs in all species but is most often diagnosed in horses and small companion animals. The causes are many; they nutrition, trauma, poisonings, conformation, growth rate problems and ageing. The problem is characterised by degeneration and erosion of the joint articular surface, degeneration of the underlying bone and hypertrophy of the surrounding bone. (See OSTEOARTHRITIS.)
Rheumatoid arthritis A chronic form of inflammatory arthritis, often accompanied by fever and usually with symmetrical involvement of several joints. There may be a genetic predisposition to the condition.
Open-joint injuries may lead to an acute septic arthritis following infection. Prompt treatment often leads to a full recovery.
Septic Arthritis can involve one joint when it is local; it can be result from injury or from an infection entering, when several joints may be involved. Both forms occur in all species and in some there are some specific causes, such as Streptococcus suis in pigs.
An operation to fix a joint in a given position. By this means a pain-free, stable and strong joint can be achieved e.g. in cases of osteoarthrosis of the carpus to correct osteoarthritis or carpal VALGUS.
(See GENETICS, HEREDITY AND BREEDING - GENETIC DEFECTS.)
A surgical repair of a joint to replace, repair or realign a JOINT. This is done in OSTEOARTHRITIS to relieve pain and restore function.
(adjective, Arthropodal)
These are members of the Phylum Arthropoda. They are very widely distributed and include arachnids (MITES, TICKS, SPIDERS), crustaceans (CRABS, SHRIMPS); insects (BEES, FLEAS, FLIES, LICE). They form a major part of the animal ecology (over 740,000 species within 12 Classes) and are parasites, saprophytes and many perform only beneficial functions. They have an exoskeleton, a hard segmented body and are BILATERALLY symmetrical.
The application of endoscopic techniques to the study of joint cavities.
Degenerative disease of a joint, as opposed to inflammation. (The word can also mean an articulation.)
An apparent lesion in a histological or pathological specimen, not existing during life, but made accidentally in preparing the specimen.
In racing greyhounds, badly fractured scaphoids have been removed and replaced with plastic prostheses. (A dog called Hare Spy won a race on January 16, 1958, after such an operation.)
(See PARTURITION, DRUG-INDUCED.)
The introduction of male germ cells (spermatozoa) into the female without actual service.
The practice is a very old one. In the 14th century Arab horse-breeders were getting mares in foal by using semen-impregnated sponges. In Italy, bitches were artificially inseminated as long ago as 1780, and at the close of the 19th century the practice was applied, to a very limited extent, to mares in Britain.
It was the Russian scientist Ivanoff who saw in AI the possibilities of disease control, and in 1909, a laboratory was established in Russia for the development and improvement of existing techniques. By 1938, well over a million cattle and 15 million sheep had been inseminated in the USSR, where all the basic work was done. Denmark began to take a practical interest in AI in 1936 (and within 11 years had 100 cooperative breeding stations inseminating half a million head of cattle annually); the USA in 1937. The technique quickly spread to other countries.
The UK began to practise AI on a commercial basis in 1942, and by the end of 1950 had close on a hundred centres and sub-centres in operation, serving over 60,000 farms. The introduction of prostaglandins in 1975 enabled synchronisation of oestrus in groups of cattle, greatly facilitating the use of AI. Since 1986, ‘do-it-yourself’ on-farm AI has been permitted after stockmen have received suitable training and the storage of semen has been adequately monitored. About 93 per cent of dairy cows are produced by artificial insemination and about a third of suckler beef cattle.
Uses The use of AI in commercial cattle breeding is dependent upon the fact that, in normal mating, a bull produces up to 500 times as much semen as is required to enable one cow to conceive. By collecting the semen, diluting it and, if necessary, storing it in a refrigerator, the insemination of many cows from one ejaculate becomes possible.
AI reduces the spread of venereal disease, and hence greatly reduces the incidence of the latter. Farmers in a small way of business are able to dispense with the services of a communal bull – an animal seldom well bred and often infected with some transmissible disease. At the same time, the farmer has the advantage of the use of a healthy, pedigree bull without the considerable expense of buying, feeding, and looking after it. Owners of commercial herds are enabled to grade them up to pedigree standard, with an increase in quality and milk yield or just to genetically improve them. In many of the ranching areas overseas, where stock-raising is carried out on an extensive, rather than an intensive, scale, to achieve satisfactory production of animals for trade and commercial purposes, sires have to be imported at regular intervals from the essentially sire-producing countries – of which Britain is the chief. The method of artificially inseminating a large number of females from an imported sire enables bigger generations of progeny to be raised and consequently more rapid improvement to be achieved.
Methods Various methods are employed to collect semen. Those which give best results involve the use of an artificial vagina in which to collect the semen from an ejaculation. This is used outside the female’s body, being so arranged that the penis of the male enters it instead of entering the vagina. The full ejaculation is received without contamination from the female.
After the ejaculate has been collected it is either divided into fractions, each being injected by a special syringe into the cervix or uterus of another female in season, or – in commercial practice – it is diluted 20 times or more with a specially prepared ‘sperm diluent’, such as egg-yolk citrate buffer, and distributed into ‘straws’ (plastic tubes). Dilution rates of up to 1 in 100 have been successful, but it appears desirable to inseminate 12 or 13 million sperms into each cow.
The method requires skill to carry out successfully, and necessitates the employment of strict cleanliness throughout. (See CONCEPTION RATES.)
Artificial insemination has also been carried out in pigs (see FARROWING RATES), goats, dogs, turkeys and other birds, bees, etc. Sexed semen is now available in cattle.
Canine AI is now practised in many parts of the world. In the UK the Kennel Club reserves the right to decide whether to accept for registration puppies obtained by means of AI rather than by normal mating. Applications are usually made by the owner of the bitch. Those concerned with a newly imported breed, and who wish to widen the genetic pool, may not be able to find a suitable male for purchase and import. However, if semen from a satisfactory dog can be obtained, and DEFRA agrees to its import under licence, AI may be a good way of increasing the available pool.
Registrations will not be accepted where AI is requested because either the prospective sire or dam is unable to mate owing to disease.
Horse AI is used widely both with chilled semen and deep-frozen semen.
Pig AI is now commonly used in commercial pig herds. Usually it is ‘extended life’ but not frozen semen. The semen is in a plastic sachet and fitted to a catheter with a plastic plug at the end that fits into the sow’s cervix
Turkey AI Farmed turkeys are now bred as male and female lines. Female lines are comparatively slender, with high egg production. Male lines are bred for meat and are much heavier. The resulting disparity between the sizes of the male and female is such that natural mating would result in injury to the female. Most turkey breeding is therefore by artificial insemination. Disposable straws, discarded after use, are used to prevent transmission of infection (notably Mycoplasma meleagridis and E. coli) but as semen is pooled from several stags, an infected stag can result in many infected hens. The technique of insemination and collection of semen requires skill. In order to ensure the hen have no eggs in the oviduct, insemination should take place at about 16.00 hours.
Sheep and Goat AI It is not usually undertaken; it is mainly used on some pedigree farms.
Birds of Prey AI Artificial insemination has been used successfully in imprinted (trained) birds of prey.
Storage of semen Diluted semen may be stored at AI centres for a few days if kept at a temperature of 5° C (41° F). In practice, a good deal would be wasted because its fertilising power has diminished before it is all required for use. However, bull semen may be stored for long periods when glycerol is added to the sperm diluent. This enables the semen to be stored and transported at –196° C (-321° F), using liquid nitrogen to maintain the low temperature. The advantages of this method are many. There is less wastage of semen, more can be stored, and the semen of any particular bull can be made available on any day. It is possible for several thousand cows to be got in calf by a given bull. The disadvantages of using a given bull or bulls too widely must be borne in mind, but that is a matter of policy and not of technique. Poor storage and/or thawing technique affects semen viability, hence successful fertilisation.
Infected semen Viruses (including that of foot-and-mouth, BVD) and mycoplasmas have, on occasion, been found in stored semen. (See also RABIES; CONTROLLED BREEDING.)
(See PIGLETS – ARTIFICIAL REARING.)
This is resorted to in: (1) cessation of respiration while under general anaesthesia; (2) cases of drowning when the animal has been rescued from the water – chiefly applicable to the small animals; (3) poisoning by narcotics or paralysants; (4) cases of asphyxia from fumes, smoke, gases, etc.
Horses and cattle Release from all restraint except a loose halter or head collar, extend the head and neck to allow a straight passage of the air into the lungs, open the mouth, and pull the tongue well out. Should the ground slope, the horse must be placed with its head downhill. While such adjustments are being carried out one or two assistants should compress the elastic posterior ribs by alternately leaning the whole weight of the body on the hands pressed on the ribs, and then releasing the pressure about once every 4 or 5 seconds, in an endeavour to stimulate the normal movements of breathing. As an alternative in a larger animal, a heavy person may sit with some vigour astride the ribs for about the same time, rise for a similar period, and then sit back again. If no response occurs, these measures should be carried out more rapidly.
The inhalation of strong solution of ammonia upon a piece of cotton-wool and held about a foot from the upper nostril often assists in inducing a gasp which is the first sign of the return to respiration, but care is needed not to allow the ammonia to come into contact with the skin or burning will occur. After 2 or 3 minutes’ work the animal should be turned on to the opposite side to prevent stasis of the blood. Sometimes the mere act of turning will induce the premonitory gasp. So long as the heart continues to beat, no matter how feebly, the attempts at resuscitation should be pursued. Proprietary calf resuscitators are available to give the ‘kiss of life’.
Pigs and sheep The outlines of procedure given for the larger animals are equally applicable. An ordinary domestic funnel can be used for giving pigs the ‘kiss of life’.
The method of giving the ‘kiss of life’ to a piglet is to use a flexible polyethylene funnel, and fit this over the animal’s mouth and nostrils. Air is blown into the stem of the funnel, and passes down into the piglet’s lungs.
For the method to be effective, the procedure is as follows: (1) hold the piglet by its hind legs with head down in order to drain any fluid from its air passages; (2) turn the piglet with its head upwards and apply the funnel; (3) blow forcefully into the funnel; (4) remove the funnel and allow the piglet to breathe out; (5) repeat the operation. After several repetitions, the piglet should kick or show other signs of life. Lay the animal on its side or stomach and massage its chest and mouth. Piglets apparently stillborn may sometimes be revived by this method.
Piglets have been revived up to half an hour after treatment began. Of course, the heart must be beating and resuscitation started promptly to achieve success.
Dogs and cats A modification of the Schafer system is to lay the dog on its side with the head at a lower level than the rest of the body, place a hand flat over the upper side of the abdomen and the other on the rib-cage, lean heavily on the hands, and in a second or two release the pressure.
The motions of artificial respiration should in all cases be a little faster than those of normal respiration, but a slight pause should always be observed before each rhythmic movement. Use less pressure for cats.
A respiratory stimulant DOXAPRAM may be given by injection. If the anaesthetic machine has the facility, carbon dioxide may be introduced to the recovery mixture at less than 10 per cent of the oxygen flow rate. Insertion of a hypodermic needle in the nasal filtrum (the vertical groove seen on the outside of the nose separating the left and right sides) can stimulate respiration – a well-recognised acupuncture site.
Rabbits and Rodents Artificial respiration in these species must be approached with great care as they are much smaller than the hand that has to affect the procedure. Gentle pressure on the chest wall with the animal in lateral recumbency may assist but endotracheal intubation and direct insufflation of the lungs is a better option.
Reptiles General anaesthesia requires endotracheal intubation and positive pressure ventilation, and as reptiles are so easy to intubate artificial respiration is best applied in this manner.
Birds A similar procedure to reptiles may be adopted but gentle, intermittent digital pressure on the sternum may suffice – movement of the avian sternum is vital for respiration.
Fish Often they can be resuscitated by drawing the whole body ‘backwards’ (i.e. caudally) in fresh water so that oxygen is passed over the gills.
A class of worms belonging to the round variety or Nemathelminthes, which are found parasitic in the intestines of horses, pigs, dogs, cats, birds and reptiles particularly, although they may affect other animals. They attain a size of 38 cm or 45 cm (15 in or 18 in) in the horse, but are small in other animals. (See ROUNDWORMS.)
A roundworm in pigs which is transferred from the sow to offspring. Following ingestion the larvae migrate out of the intestine and go to the liver. As they mature they go to the lungs before being coughed up and then maturing in the intestines. Respiratory signs can occur in the growing pig and can be part of the PORCINE RESPIRATORY DISEASE COMPLEX. In the intestines they can reduce weight gain or on occasions block the intestines. They can be removed with anthelmintics.
OEDEMA involving the abdomen; a very common complication of abdominal tuberculosis, of liver, kidney, or heart disease, as well as of some parasitic infestations. In poultry, ascites is sometimes associated with hypoxia (‘high altitude disease’) although there are other causes including toxins or, in individuals, heart defects or abdominal tumours. It is also seen in ducks with furazolidone poisoning.
Vitamin C. It is found in many vegetables and fruits especially citrus fruits and naturally synthesised in most animals except primates, fruit bats, guinea pigs and some fish. A vitamin C-responsive condition is seen in animals such as calves following prolonged diarrhoea. Some connective tissue disorders such as EHLERS-DANLOS SYNDROME (see CUTANEOUS ASTHENIA) in rabbits are said to show some response to therapeutic doses.
The addition of ascorbyl monophosphate to cat diets has resulted in 20 per cent reduction in plaque formation and a 14 per cent reduction in calculus formation after a 28-day period.
The absence of pathogenic organisms. Aseptic surgery is the ideal, but among animals it may be difficult to attain if carried out under farm conditions – despite care in sterilising instruments and the use of sterilised dressings, rubber gloves, etc. Moreover, it is an exceptionally difficult matter to prevent accidental infection in a surgical wound after the operation, for the animal cannot be put to bed, and it may object to the dressings and do all in its power to remove them. (See ANTISEPTICS; SULFONAMIDES; PENICILLIN.)
Poisoning by Fraxinus species has been reported in cattle after eating the green leaves and fruits from a broken branch of a tree. Signs include: drowsiness, oedema involving ribs and flanks, and purple discoloration of perineum.
Also called SERUM GLUTAMIC OXALO-ACETATE AMINOTRANSFERASE (SGOT or GOT). The serum levels tend to rise when tissues are damaged such as LIVER, HEART and MUSCLE.
An amino acid used in the formation of RNA and DNA. It appears to be involved in protecting the liver, promotes normal cell formation and it is useful in endurance situations.
A disease of mammals and birds produced by the growth of the fungus Aspergillus in the tissues of the body.
Infection probably occurs chiefly through inhalation of the fungal spores, which may be abundant in hay or straw under conditions of dampness. Entry of the spores into the body may also be by way of the mouth; in herbivorous animals from contaminated fodder or bedding; and in cats and dogs from the eating of infected birds or rodents.
Once in the animal’s tissues, hyphae grow out from the spores, as happens also in ringworm; and from the branching filaments more spores are produced. Local necrosis and abscess formation are caused.
Numerous organs and tissues can become infected, including the nose and nasal sinuses, the lungs, brain, uterus, and mammary glands.
Cattle and horses Aspergillus may cause abortion and lung sensitisation or pneumonia.
Dogs and cats Aspergillosis is a common cause of chronic nasal disease, and should be suspected when there is a discharge from one nostril.
Poultry Respiratory disease or enteritis may occur. In young turkey poults brain involvement has led to an unsteady gait, walking backwards, and turning the head to one side.
Birds Pet parrots and birds of prey kept for breeding or falconry may die from aspergillosis, as can wild birds. Sources of infection include contaminated feed and litter on aviary floors.
Brain infection may occur in all species and give rise to signs described under ENCEPHALITIS. Paresis and ataxia may, rarely, be caused by fungal infections of the spine.
Ketonazole, given by mouth, and irrigation of the sinuses by enilconazole in sodium chloride solution have been used in cases of canine nasal aspergillosis. Oral antimycotic agents such as itraconazole and topical antimycotics such as enilconazole (by nebulisation) are often used in parrots but with variable results.
(See BOG ASPHODEL.)
Suffocation may occur during the administration of anaesthetics by inhalation, during the outbreak of fires in animal houses, where the fumes and the smoke present are responsible for oedema, and in cases of poisoning. (See also ‘KITCHEN DEATHS’.)
Signs The direct cause of death from asphyxia is an insufficiency of oxygen supplied to the tissues by the blood. The first signs are a rapid and full pulse, and a quickening of the respirations. The breathing soon changes to a series of gasps, and the blood pressure rises, causing the visible membranes to become intensely injected and later blue in colour. Convulsions supervene. The convulsions are followed by quietness, when the heartbeat may be almost imperceptible and respiratory movements practically cease. The actual time of death is unnoticed as a rule, since death takes place very quietly.
During the stage of convulsions, when the amount of carbon dioxide circulating in the blood is increased, the smaller arteries vigorously contract and cause an increase in the blood pressure. This high blood pressure produces an engorgement of the right side of the heart, which cannot totally expel its contents with each beat, and becomes more and more dilated until such time as the pressure in the ventricles overcomes the strength of the muscle fibres of the heart and the organ ceases to beat. During this stage immediate relief follows bleeding from a large vein.
Treatment (See ARTIFICIAL RESPIRATION.) If the breathing is shallow and the membranes livid, administration of OXYGEN is indicated.
Prevention Ensure adequate ventilation in rooms where there is a gas or solid-fuel heating system. (Many dogs and cats have been found dead in the kitchen in the morning as a result of CARBON MONOXIDE poisoning.)
(See PARACENTESIS.)
It is the oldest known non-steroidal anti-inflammatory drug (NSAID). An analgesic; also used in prevention of thrombosis. It is available in tablet and powder form.
Must be used with extreme caution and under professional supervision in cats; the dose not exceeding 10 mg/kg on alternate days.
In both cats and dogs, overdosing with aspirin may cause inflammation of the stomach, haemorrhage, some pain and vomiting. The antidote is sodium bicarbonate which can be given in water by stomach tube; or, for first-aid purposes, by the cat-owner, in milk or water. (See SALICYLIC ACID AND SALICYLATES - SALICYLATE POISONING.)
Aspirin has been used to lessen the effects of PORCINE REPRODUCTIVE RESPIRATORY SYNDROME (PRRS/blue-eared pig disease).
In horses it can be used in large doses of 100mg/kg to lower the requirement of phenylbutazone for treating chronic laminitis.
Absence of the spleen, or its failure to function.
Address: PO Box 46, Worcester, WR8 9YS. Telephone: 01386 75115; email: info@apbc.org.uk; website: www.apbc.org.uk.
Address: APDT, PO Box 17, Kempsford, GL7 4WZ. Telephone: 01285 810811; email: info@apdt.co.uk; website: www.apdt.co.uk.
(See ASPARTATE TRANSFERASE.)
Asthenia is another name for debility. Asthenic is applied to the exhausted state that precedes death during some fevers.
Asthma is a term somewhat loosely applied to a number of conditions in which the main sign is breathlessness. Strictly speaking, the term should be reserved for those conditions where a true spasmodic expulsion of breath occurs without the effort of a cough. The so called ‘asthma’ of birds is due in nearly every case to ASPERGILLOSIS. Asthma in horses may be difficult to differentiate from ‘BROKEN WIND’ also called RECURRENT AIRWAY OBSTRUCTION (RAO), and in all animals from simple BRONCHITIS.
Causes These are obscure, but it is generally held that true spasmodic asthma is of nervous origin, and due to a sudden distressful contraction of the muscle fibres which lie around the smaller bronchioles. In some cases asthma may be an allergic phenomenon. In other cases a chronic inflammation of the lining mucous membrane of the small tubes is the cause.
The spores of fungi are potent allergens, and can account for many cases of asthma, especially recurrent summer asthma, in man. There are, however, a number of patients with seasonal (summer or autumn) asthma who are not sensitive to spores of any of the above nor to pollen. (See ALLERGY.)
Dogs Many cases that are really chronic bronchitis are spoken of as ‘bronchial asthma’ owing to their similarity to asthma in man, with which many owners of animals are familiar. In true asthma, the attacks of dyspnoea (i.e. distressed respiration) occur at irregular intervals, and there are periods between them when the dog is to all appearances quite normal. The attacks occur suddenly, are very distressing to witness, last for 10 minutes to half an hour, and then suddenly cease. The dog gasps for breath, makes violent inspiratory efforts without much success, exhibits a frightened, disturbed expression and stands till the attack passes off.
The condition appears to be hereditary in some breeds, especially the Maltese terrier. Cardiac dysfunction also gives rise to ‘asthma’ due to pulmonary oedema. (See also ATOPIC DISEASE.)
Treatment Bronchodilators, such as amino-phylline, clenbuterol or ephedrine, and antihistamines or heart stimulants may be of service. The treatment used will depend on the cause of the problem; e.g., diuretics are useful in cases of pulmonary oedema due to heart failure. Regulation of exercise and diet is necessary. (See also CHRONIC OBSTRUCTIVE PULMONARY DISEASE; BRONCHITIS.)
The congenital absence of the mouth.
Astragalus (Talus) is the name of one of the bones of the tarsus (hock), with which the tibia forms the main joint. The articulation between these bones is sometimes referred to as the ‘true hock joint’, the others being more or less secondary and less freely movable joints.
Substances which contract tissues and stop discharges; they include sulphate of zinc, alum, tannic acid, witch-hazel.
Supporting cells found in the central nervous system, and each consisting of a cell body and numerous branching processes. Astrocytes are thought to be concerned with the nutrition of neighbouring nerve cells. They may also be involved in the tissue damage which occurs in cases of stroke.
Astrovirus was first detected in the faeces of children in 1975, and has since been isolated from lambs, calves, turkeys, deer, etc. It is not regarded as a serious pathogen in veterinary medicine, but studies in gnotobiotic lambs indicate that the virus multiplies in the epithelial cells of the villi of the small intestine, producing some degree of atrophy of the villi, with diarrhoea.
Outbreaks of a lop-sided condition of the hindquarters in the pig, known as asymmetric hindquarter syndrome, have been described by J. T. Done and others. This condition has been seen in Germany, Belgium, and Britain.
AHQS, which would appear to have a hereditary basis, could be of economic importance since it affects carcase conformation, and could lead to carcase condemnation.
The abnormality does not usually become obvious before pigs reach about 30 kg (66 lb) liveweight, when one thigh may be seen to be much smaller than the other though of the same length. Even in severe cases it was observed that the gait was normal.
The incidence of AHQS within litters of affected families varies from 0 to 80 per cent, and the breeds involved include Large White, Hampshire and Lacombe.
This means the absence of clinical signs, as is seen in the ‘CARRIER’ animal or the carrier state.
The lack of continuity in an organ or tissue.
A failure of the heart to contract, generally due to the walls having become so weak that they are unable to contract and expel the blood, with the result that the organ becomes distended – a feature found after death.
Asymmetric Hindquarter Syndrome (AHQS).
A ‘throw-back’ in the genetic sense. It is a factor that has been dormant or not expressed for several generations and then reappears in an individual or indivduals.
Ataxia means the loss of the power of governing movements, although the necessary power for these movements is still present. A staggering gait results. Ataxia is a sign which may be observed in many diverse conditions, for example, rabies, weakness or exhaustion, encephalitis, meningitis, poisoning and a brain tumour. It may be seen in all animals.
Cattle A progressive form of ataxia of probably inherited origin has been found in French-bred Charolais heifers, with signs first appearing in the first year: slight intermittent ataxia progresses to recumbency over 1 to 2 years. Urine is passed in a continuous but uneven squirting flow. When excited, affected heifers may show nodding of their heads.
Cats Ataxia is seen in feline infectious peritonitis poisoning by ethylene glycol (anti-freeze), alphachloralose, and streptomycin, for example, and before eclampsia (lactation tetany). Congenital cerebellar ataxia may be seen in kittens, usually when born to mothers infected with parvovirus (see FELINE INFECTIOUS ENTERITIS). There is uncoordinated movement of the head, especially when feeding, and they stand with their legs apart to aid balance. The condition does not worsen and, unless very serious, kittens usually adapt well.
Failure of the fetal lungs to expand at birth, either partial or complete.
The imperfect development of the brain, same as ATELENCEPHALIA.
An incomplete development of the heart.
An incomplete development of the hand.
The imperfect development of the brain, same as ATELENCEPHALIA.
A development defect of the foot (hindlimb).
The incomplete development of the mouth.
A degenerative change in the inner and middle coats of the arteries in which a deposit of lipid material is formed. (See ARTERIES, DISEASES OF.) In the horse it is also an epidermal inclusion cyst of the false nostril.
A condition in which deposits of cholesterol and other material in the inner lining (intima) of arteries restricts the blood flow. It is seen quite commonly in captive birds of prey and caged parrots with inadequate diets.
The absence of the thymus gland and its secretions.
This is an α-2 adrenergic receptor agonist used to reverse the sedative, analgesic, cardiovascular and respiratory effects of medetomidine in dogs and cats.
Atlas is the name given to the 1st of the cervical vertebrae, which forms a double pivot joint with the occipital bone of the base of the skull on the one hand, and forms a single gliding pivot joint with the epistropheus or axis – the 2nd cervical vertebra – on the other hand. The freedom of movement of the head is due almost solely to these 2 joints.
A malformed fetus with one body and two heads; a synonym for dicephalus.
Atony means want of tone or vigour in muscles or other organs. (See also TONICS.)
An often seasonal condition which involves pruritus, frequently of the feet, face and the ventral abdomen with self-trauma. There may be secondary pyoderma, otitis externa and excessive sweating (hyperhidrosis). It is particularly seen in dog breeds including ENGLISH SETTERS; WEST HIGHLAND WHITE TERRIERS; WIRE-HAIRED FOX TERRIERS; YORKSHIRE TERRIERS.
A hypersensitivity to pollens and other inhaled protein particles. (See ALLERGY.) There is intense itching affecting the feet, abdomen, and face as well as sneezing, conjunctivitis, rhinitis and asthma; there may be some discoloration of the coat. In allergy tests on 208 dogs, about 40 per cent were found to be hypersensitive to human dandruff.
The condition was originally thought to be due to allergic dermatitis due to inhalation of allergens. It is now recognised to be very complex and due to immune dysfunction and allergic reactions that can be either food induced or non-food induced. In dogs, it starts under three years old, mainly in animals living indoors. There is PRURITUS before there are any skin lesions affecting the front feet and inside of the ear flap, but not the ear margins or the upper body, and it responds to GLUCOCORTICOID treatment. It is often inherited and is seen in breeds such as DALMATIANS.
Atopic disease also occurs in cats and cattle (See BOVINE ATOPIC RHINITIS).
A syndrome mainly seen in dogs where there is a Type 1 hypersensitivity (an allergy) often due to an inherited predisposition. IgE (immunoglobulin E) is involved.
(See ADENOSINE - ADENOSINE TRIPHOSPHATE.)
Atresia means the absence of a natural opening, or its obliteration by membrane. Atresia of the rectum is found in newly-born pigs, lambs, calves, and foals. Atresia is sometimes met with in heifers with one or both uterine horns absent, when it constitutes what is known as ‘WHITE HEIFER DISEASE’. Atresia of the cloaca has been recorded in African Grey parrots (Psittacus erithacus erithacus).
It is a congenital condition resulting in the absence of faeces and the anus closed off resulting in the abdomen swelling. There is usually a dimple where the anus should be and the anal sphincters are often developed. Surgical correction is often possible and undertaken in dogs and some other species.
The absence of the normal opening(s) (cardiac and/or pyloric orifices) of the stomach.
An imperforation of the urethra.
(singular, Atrium)
In birds these are found in the lungs, and are small air vesicles which radiate out from the PARABRONCHI and are where exchange of gases occurs.
Relating to the atrium or AURICLE of the heart.
A congenial condition in which there is a septal defect between the two atria (a ‘hole in the heart’). This is because of a failure of the normal closure mechanisms of the ostium primum and ostium secondum. It is seen in all animals, but is rare. In dogs, some breeds are more susceptible, including BOXERS.
Absence of hair.
It is responsible for transmitting the impulse from the atria (auricles) of the heart to the ventricles. Also known as Purkinje tissue.
(See AURICLE.)
(See under MUSCLES, DISEASES OF.)
A disease of pigs affecting the nasal passages. (See under RHINITIS, ATROPHIC, INCLUSION BODY RHINITIS.)
Atrophy is a wasting of the tissues. Following paralysis of a motor nerve, when the muscles supplied by it are no longer able to contract, atrophy of the area takes place. This is seen in paralysis of the radial nerve. (Compare HYPERTROPHY.)
Disuse Atrophy occurs when muscles are not used for a long period, for example when a limb is not used for locomotion because of a painful lesion or injury located somewhere in the limb.
An alkaloid contained in the leaves and root of the deadly nightshade (Atropa belladonna). Preparations of belladonna owe their anticholinergic actions to the presence of atropine, which blocks transmission at sensory nerve-endings and thus relieves pain and spasm in parts to which it is applied. It checks secretion in all the glands of the body when given internally; and whether given by the mouth or rubbed on the skin it causes a dilatation of the pupil of the eye and paralysis of accommodation. In large doses it induces a general stimulation of the nervous system, but this action is rapidly followed by depression, and the primary effect is not noticed in the administration of ordinary doses. The action on the heart is one of stimulation, since the inhibition fibres are paralysed, while the accelerator nerves are not interfered with, except when large doses are given and paralysis of all motor fibres occurs.
Uses Atropine is used as a premedicant to anaesthesia as it reduces respiratory tract secretions. It is also used to dilate the pupil in order to facilitate eye examinations, and to reduce salivation in mouth and dental operations. As an antidote to morphine poisoning and also to some of the organophosphorus compounds used as farm sprays, it is given as the sulphate of atropine by hypodermic injection.
Atropine poisoning may occur as the result of the unintentional administration of too large amounts of the alkaloid ATROPINE or of the drug BELLADONNA in one form or another, or it may be induced by feeding on the plant growing wild.
The signs of poisoning shown are restlessness, delirium, dryness of the mouth, a rapid and weak pulse, quick, short respirations, an increase in temperature, and dilatation of the pupil. In addition there is sometimes seen a loss of power in the hind-limbs.
Antidotes To those animals that vomit, an emetic should be given at once if the poison has been taken by the mouth. Horses and cattle should have their stomachs emptied by the passage of the stomach-tube, in so far as that is possible. Stimulants should be given, and pilocarpine, by injection, is the antidote.
A clay which is used in the treatment of non-specific diarrhoea. Toxins adhere to the substance and then pass out in the faeces. (See also BONE CHARCOAL).
A term used to describe a reduction in the virulence of a micro-organism, particularly applied to those incorporated in VACCINES.
The auditory nerve (acoustic nerve) is the 8th of the cranial nerves, and is concerned with the special sense of hearing. It arises from the base of the hind-brain just behind and at the side of the pons. It is distributed to the middle and internal ears, and in addition to its acoustic function it is also concerned with the balance of the body. (See EAR.)
A fetus with a double lower jaw.
A viral disease, primarily of pigs. It is also known as pseudorabies and infectious bulbar paralysis. It can occur in other species; the infection usually being contracted from contact with pigs or consumption of pig carcases. The disease has a very short incubation period, and is characterised by intense itching. It was first described in Hungary by Aujeszky in 1902, and has been eradicated from the UK, Denmark, Sweden and parts of other countries in the EU. It has also been found in several parts of the USA, South America, Australia, the continent of Europe, etc. In the UK, the disease is NOTIFIABLE and an eradication campaign began in 1983. Monitoring continues by sampling cull animals at slaughterhouses. The infection may be windborne. Vaccines are available, but their use is prohibited in the UK except Northern Ireland. However, gene-deleted vaccines can be used in eradication programmes as it is possible to differentiate serologically a pig which has been vaccinated from one which has been exposed to infection.
Signs
Pigs Signs include abortion, sneezing, anorexia and dullness besides some evidence of pruritus, vomiting, diarrhoea, convulsions, drooling of saliva and paralysis of the throat. Mummification of the fetuses may occur in pregnant sows affected with Aujeszky’s disease. Such sows may show loss of appetite and constipation, or stiffness and muscular incoordination without itching at all. For the screening of pig serum samples, the ELISA test has been found the most sensitive, speediest and cheapest of four methods for detecting antibodies to Aujeszky’s disease virus. (Central Veterinary Laboratory.)
Prevention: Intranasal vaccination with attenuated virus is more effective than parenteral vaccination with inactivated virus, as maternally derived antibodies interfere with the latter.
Dogs and cats Restlessness, loss of appetite, vomiting, salivation, signs of intense irritation (leading to biting or scratching) about the face or some other part, and occasionally moaning, groaning, or high-pitched screams are among the signs observed. Many cases are seen as deaths overnight in previously healthy animals following eating infected meat.
In one outbreak, 11 out of a pack of 51 harrier hounds died of the disease (apparently as a result of being fed raw carcase meat from a large pig unit). Infected rats may be another vector.
Cattle The first sign to be observed is usually a persistent licking, rubbing or scratching of part of the hindquarters (or sometimes of the face) in an attempt to relieve the intense itching. The affected part soon becomes denuded of hair, and may be bitten and rubbed until it bleeds. This has produced the name of ‘Mad itch’. Bellowing, salivation and stamping with the hind-feet may be observed. Within 24 hours the animal is usually recumbent and unable to rise on account of paralysis. Death, preceded by convulsions, usually occurs within 36 to 48 hours of the onset of signs.
Goats Deaths have occurred in goats kept with infected pigs. Signs include restlessness, sweating, distressed bleating and convulsions; some animals may be found dead without signs being noticed.
Poultry One-day-old chicks have died after being inoculated with a Marek’s disease vaccine. Aujeszky’s disease vaccine virus adapted to chicken cells was likely to have been the cause.
Horses The virus was isolated from the brain of a horse showing the following signs: excessive sweating, muscle tremors and ‘periods of mania’.
Public health Aujeszky’s disease virus can infect people, but it seems that only laboratory workers are likely to find this a health hazard.
Relating to the ear.
(See AURICULAR CARTILAGES.)
The auricles, right and left, are the chambers at the base of the heart which receive the blood from the body generally, and from the lungs respectively. Opening into the right auricle are the cranial and caudal vena cavae, which carry the venous blood that has been circulating in the head and neck and the abdomen and thorax. This blood is pumped into the right ventricle through the tricuspid valve. Opening into the left auricle are the pulmonary veins which bring the arterial blood that has been purified in the lungs; when this auricle contracts the blood is driven into the left ventricle through the mitral valve. (See HEART; CIRCULATION OF BLOOD.)
Auricular cartilages are the supporting structures of the ears. There are three chief cartilages in most animals, viz. the conchal, which gathers the sound waves and transmits them downwards into the cavity of the ear and gives the ear its characteristic shape; the annular, a cartilaginous ring below the former which is continuous internally with the bony acoustic canal; the scutiform, a small quadrilateral plate which lies in front of the others and serves for the attachment of muscles which move the ear.
Accidents and diseases of the cartilages of the ear are not common in animals, with the exception of dog/cat fights. Ulceration of the cartilages, chiefly the annular, occurs as a complication of ear inflammation in the dog. Laceration of the conchal cartilage is seen as the result of the application of a twitch to the ear in the horse.
Auscultation is a method of diagnosis by which the condition of some of the internal organs is determined by listening to the sounds they produce. Auscultation is practised by means of the stethoscope.
It is found in small numbers in the UK. Progressive retinal atrophy may be found in this breed, but with an unknown mechanism of inheritance.
Working dogs which possibly originated from the AUSTRALIAN CATTLE DOG but which were developed in the Western USA. The breed is mainly found in the USA and there are very few in Australia. The dog has medium length black, red, blue merle and red merle, is usually tailless and is a medium-sized breed (male 23 kg to 29 kg, female 18 kg to 20 kg). It has several potential defects including COLLIE EYE ANOMALY, CATARACT, and PROGRESSIVE RETINAL ATROPHY (due to a recessive trait).
A breed of dog resembling large (3 kg to 4 kg) YORKSHIRE TERRIERS, with a silky coat coloured blue or grey with tan. They can show PROGRESSIVE RETINAL ATROPHY.
Derived from cattle dogs originally from England crossed with dingos. Found in relatively small numbers in the UK. They have a dense, straight-haired coat speckled red or speckled blue in colour. They are smaller than the AUSTRALIAN CATTLE DOG and have a stumpy tail. They males are 46 cm to 50 cm (18 in to 20 in) at the shoulder and weigh 15 kg to 20 kg (33 lb to 44 lb). They can suffer from PROGRESSIVE RETINAL ATROPHY, due to a recessive trait.
A small terrier (6 kg to 7 kg) with short legs, erect ears, docked tail and a harsh medium-length coat. They can show VON WILLEBRAND’S DISEASE.
This breed comes from Australia. It is black with a green sheen to its feathers. The male is about 4 kg (9 lb) and the female 3 kg (6.5 lb). They produce about 250 light brown eggs per year.
In veterinary use, the term describes the seeding of the digestive tract with normal flora and fauna in all species and is especially important in herbivores. It refers particularly to the rumen in ruminants and the caecum in rabbits and horses. Usually these micro-organisms are obtained from the parents or others of the same species in a herd, and come mainly from environmental exposure.
Autogenous means self-generated, and is the term applied especially to bacterial and viral vaccines manufactured from the organisms found in discharges from the body and used for the treatment of the particular individual from which the bacteria were derived.
Auto-immune disease is due to a failure of the bodily defence mechanisms in which antibodies become active against some of the host’s own cells. The cause, as far as is understood, is an overproduction of interferon-α. This results in an immune-stimulating protein being produced and precursor dendritic cells then grow into mature cells while still in circulation. In this situation they digest host DNA and produce chemicals against the host’s DNA. Normally such dendritic cells are removed by the thymus gland and the peripheral tolerance mechanism, but this fails in the presence of excess interferon-α. One of the original descriptions of such disease was Hashimoto’s thyroiditis in humans. In animals, an example is spontaneous auto-immune thyroi-ditis which occurs in dogs, poultry, monkeys and rats, and resembles Hashimoto’s thyroiditis of man. Other examples are auto-immune haemolytic disease, in which the blood’s red cells are affected; and glomerulonephritis in small animals.
Immune-mediate diseases are of two kinds: (1) primary, an auto-immune reaction only against self; and (2) secondary, a similar reaction occurring when viruses, tumours, parasites or drugs are involved.
Drugs are being developed to suppress interferon-α production if it appears that an auto-immune disease is developing. A Type 1 reaction is one where the antibodies are directed against the body itself, whereas a Type 2 reaction is directed against the antibody complex formed by the body and is seen in some cases where herpes viruses are involved.
Primary diseases are either organ-specific, e.g. auto-immune haemolytic anaemia (see under ANAEMIA, or systemic, e.g. LUPUS ERYTHEMATOSUS. (See also THROMBOCYTOPENIA; POLYARTHRITIS; PEMPHIGUS; BOVINE and CANINE AUTOIMMUNE HAEMOLYTIC ANAEMIA; DIABETES MELLITUS.)
Infection of one part of the body, hitherto healthy, from another part that already is suffering from the disease. Thus, sheep suffering from ‘orf’ on their feet may bite the painful areas and convey the organisms to their mouth, where the disease becomes established.
It is a condition where toxins build up in the body of an animal and cause illness.
Derived from the same animal.
Self-digestion of an organism by its own enzymes. (See also NECROSIS.)
The autonomic nervous system is that part of the nervous system which governs the automatic or non-voluntary processes. It governs such functions as the beating of the heart, movements of the intestines, secretions from various glands, etc. It is usually regarded as composed of 2 distinct but complementary portions: the parasympathetic and the sympathetic systems.
The parasympathetic system is composed of a central portion comprising certain fibres present in the following cranial nerves: oculomotor, facial and glossopharyngeal; and the whole of the outgoing (efferent) nerves in the important vagus nerve. There is also a sacral set of autonomic nerve fibres present in the ventral roots of some of the sacral nerves.
The sympathetic system is composed of nerve fibres present in the ventral roots of the spinal nerves lying between the cervical and lumbar regions.
The two systems are mutually antagonistic in that stimulation of each produces opposite effects. These effects are shown in the form of the now classic table (see below).
Under normal circumstances there is a harmony preserved between the working of the two systems, which are flexible enough to provide for the ordinary exigencies of life. The sympathetic system is stimulated during the ‘fight or flight’ reaction, which comes into effect during emergency situations.
Organ |
Stimulation by chemical or other means of |
|
Parasympathetic |
Sympathetic |
|
|
Pupil Heart Salivary glands Stomach and intestines Pyloric, anal, and ileocaecal Bladder Bronchial muscles Gastro-intestinal and bronchial glands Sweat glands |
Contracts Slows Thin watery secretion Causes movement No action Contracts Causes contraction Produces secretion No action |
Dilates Accelerates Thick glairy secretion Inhibits movement Causes constriction Relaxes Causes relaxation No action Causes secretion |
The effect of stimulation of the parasympathetic and sympathetic nervous systems.
(See FELINE DYSAUTONOMIA.)
Autopsy (from the Greek, seeing with one’s own eyes) is the examination of the internal structures of the body performed after death. From a post-mortem examination much valuable information can be learned, especially when there has been doubt about the disease condition during life. It has been said that it is ‘unfair to the living animals, as well as a handicap to the progress of veterinary science, for owners to prohibit an autopsy because of sentiment’.
An autopsy is obligatory where some NOTIFIABLE DISEASES, e.g. rabies, are involved, so that laboratory tests may be carried out to confirm or establish diagnosis. In the case of rabies, gloves and goggles must be worn, and every precaution taken, by the person carrying out the autopsy. Examination of avian carcases, especially parrots, is performed in a Microbiological Safety Cabinet which extracts air (and infective organisms such as Chlamydophila psittaci) over the carcase and away from the technician). With other communicable diseases (see ZOONOSES) similar precautions are necessary.
Valuable information can be obtained in slaughter-houses as to the extent of a disease, such as liver-fluke infestation in cattle and sheep, over a region or indeed throughout a whole country; and if suitably recorded and collated, the information can indicate the economic importance of diseases in farm animals and so lead to disease-control measures being taken as part of a regional or national campaign.
See under WOOL BALLS IN LAMBS for an example of a layman’s misinterpretation of post-mortem findings.
Some breeds of poultry can have different feathering colours, allowing the sexes to be differentiated even at birth. Most of these have been produced by crossing two breeds until they breed pure. Examples of this are the Welbar originally produced by crossing the WELSUMMER and BARRED PLYMOUTH ROCK male and the Legbar (a cross of the LEGHORN with the BARRED PLYMOUTH ROCK). In domestic turkeys there are some strains where the, male is like a bronze turkey and the females are auburn or copper in colour and this can be seen at hatching.
A fairly normal member of asymmetric conjoined twins, the other twin being dependent on the autosite for its nutrition.
Autosomes are the chromosomes present in the nuclei of cells other than the sex-chromosomes. They are of the same type in both sexes in each species of animal, whereas the sex-chromosomes of the female are different from those of the male. (See CYTOGENETICS.)
The loss of the tail of lizards as a defence mechanism – the shed piece wiggles and distracts the predators allowing the reptile to escape. It is seen in lizards that do not require their tails for locomotion – therefore it is not seen in chameleons, monitors or marine iguanas. The shed extremity regrows, albeit without the same skin pattern. (See IGUANAS.)
A vaccine prepared from an organism isolated from an animal and injected back into the same animal. The most common auto- (or autologous) vaccine is that prepared for treatment of warts (angleberries) in cattle. See AUTOLOGOUS.
The disease is caused by Aeromonas liquefaciens in fish at a time of stress, for example, adult brown trout are vulnerable during the spawning season. Skin lesions may be invaded by Saprolegnia fungus and the abdominal skin may show severe inflammation. The internal organs are very haemorrhagic. In severe cases the kidney is liquefied. Immature fish or non-spawning adults may carry the infection.
This is a non-biting fly which is a serious pest of grazing farm livestock in the UK and elsewhere. They cause cattle to huddle together and to cease feeding. Large numbers may collect on the upper part of the body, feeding on secretions from nose, mouth, eyes and on discharges from any wounds. (See FLIES – Fly control measures.)
Plant hormones. These include oestrogens in pasture plants.
(See LEGG-CALVÉ-PERTHES DISEASE.)
A group of chemical compounds first derived from a fungus discovered in Japan in 1975, effective in very low dosage with a broad spectrum of activity against nematode parasites and also against external parasites. (See IVERMECTIN, DORAMECTIN, MOXIDECTIN.) The discovery of the fungus in a soil sample was part of Merck Sharp & Dohme’s international screening programme.
Technically, the avermectins are a series of macrocyclic lactone derivatives produced by fermentation of the actinomycete Streptomyces avermitilis. Different formulations are available for administration as injections, drenches, boluses and pour-on forms. The group includes products for cattle, sheep, pigs, and in some countries for goats. Avermectins are safely used in many animals, but are known to be toxic in CHELONIA and in some breeds of dogs, notably BORDER COLLIES and their crosses.
An adjective to describe related to or derived from birds.
A virus that has been identified as the causal agent of proventricular dilation disease (PDD) in psittacine birds. It results in high mortality and has been reported worldwide since the late 1970s. There is at post mortem dilation of the proventriculus with nervous lesions, including encephalitis, myelitis and neuritis. Besides psittacines the infection has been found in wild Canada geese (Branta canadensis) and Trumpeter swans (Cygnus buccinator).
(See under FOWL POX.)
Macrorhabdus ornithogaster previously known as Megabacterium, a pathogenic organism of the intestinal tract of cage birds. (See MEGABACTERIOSIS.)
Hens producing α-3 enriched eggs showed a higher mortality when infected with avian hepatitis virus E than normal hens.
A disease of chicks and turkey poults; also known as epidemic tremor.
Cause A picornavirus. (Infection via the egg, as well as bird to bird.)
Signs If infection is egg-borne, signs are seen in the first 10 days after hatching; if infected after hatching, at 2 to 5 weeks old. There is leg weakness, followed by partial or complete paralysis of the legs. The chicks struggle to balance with the help of their wings. Trembling of the head and neck occurs in some cases.
Diagnosis An ELISA test.
Mortality A 40 per cent rate is not unusual.
Prevention Vaccination has proved very successful.
Avian infectious laryngotracheitis of poultry is caused by a herpesvirus, prevalent in NW England. Loss of appetite, sneezing and coughing, a discharge from the eyes, difficulty in breathing are the main signs. Birds of all ages are susceptible. Mortality averages about 15 per cent. No treatment is of value. Control is best achieved by depopulation and fumigation. A vaccine has been used.
Avian influenza (it used to be called fowl plague, but the term is no longer used) attacks domesticated fowl chiefly, but turkeys, geese, ducks and most of the common wild birds are sometimes affected. It is not known to affect the pigeon. The disease is found in Asia, Africa, the Americas and to a lesser extent in parts of the continent of Europe, and is always liable to be introduced to countries hitherto free from it through the migrations of wild birds. An outbreak occurred among turkeys in Norfolk in 1963; this was the first recorded outbreak in Britain since 1929. An outbreak occurred in the Republic of Ireland in 1983; a slaughter policy followed. Infection may have come from Pennsylvania, where a similar policy was adopted.
Already in this century, there have been outbreaks of a severe form of the disease in the Netherlands, Belgium and Germany (2003) and milder outbreaks in the Americas in 2004. However, in 2004 and 2005, there was a severe series of outbreaks caused by H5N1 strain in South East Asia, Japan, China and Korea, with spread to, and mortality in, the human populations. Unusually, this virus can also infect felidae. The EU stopped all imports from the area. As a result, the OFFICE INTERNATIONAL DES EPIZOOTIES proposed a new definition of avian influenza: ‘infection by an influenza A virus that has intravenous pathogenicity index in 6-week old chickens greater than 1.2 or any influenza virus of H5 and H7 subtype.’ ‘Poultry’ covers all birds kept in captivity for the production of meat or eggs, for restocking game or for breeding.
Cause Myxovirus influenzae.
Signs In some cases the number attacked is small, while on the same premises the next year 80 per cent or 90 per cent of the total inhabitants of the runs may die. The affected birds often die quite suddenly. In other instances the sick birds isolate themselves from the rest of the flock, preferring some dark out-of-the-way corner where they will be undisturbed. They are dull, disinclined to move, the tail and wings droop, the eyes are kept closed; the bird may squat on its breast with its head tucked under a wing or in amongst the shoulder feathers; food is refused, but thirst is often shown; the respirations are fast and laboured but not impeded by mucus; the temperature is very high at the commencement (43° C to 44° C [110°F to 112° F]), but falls shortly before death to below normal. (The normal temperature of birds is 41° C [106.5° F].) The comb and wattles become purple or blue and oedema of the head and neck is common. The illness seldom lasts more than 24 to 36 hours, and often not more than six.
Control Vaccines are available but their use is incompatible with an eradication policy. They are used in parts of the USA and in Italy.
Vaccines that are prepared by passage of the antigen through egg tissue.
An infectious disease of poultry, occurring as an epidemic among young stock (often as an accompaniment of other diseases) or sporadically among adults.
Cause Listeria monocytogenes, a Gram-positive motile rod-shaped organism.
Signs In the epidemic type, wasting occurs over a period of days or even weeks. For 48 hours before death birds refuse all food.
The sporadic type is characterised by sudden death from myocarditis without much loss of condition.
Diagnosis Depends upon bacteriological methods. (See also LISTERIOSIS.)
Avian lymphoid leukosis virus (LLV) infection is widespread among chickens in the UK, and causes mortality from tumours.
This disease, which has to be differentiated from Marek’s disease, affects birds of 4 months upwards and is egg-transmitted, shows variable signs but, typically, the liver is enlarged.
It may be identified by the presence of neutralising antibodies in the serum or by virus detection by ELISA.
Control High standards of hygiene and flock management; no vaccines are available.
(See Plasmodium gallinaceum.)
(See ‘PULLET DISEASE’.)
A viral infection first detected in the UK in 1988. In chick embryos it causes stunting, haemorrhage and oedema as well as nephritis.
(See AVIPOX.)
Avian sex determination by laparoscopy has been widely used since 1976, but is losing popularity in favour of sexing by examination of DNA in avian blood including that found in emerging feathers.
The increase in the number of farmed poultry kept in free-range systems or with access to outdoors has led to an increase in the incidence of this disease. It is usually seen in birds over 2 years old but can occur in young birds. Ostriches are usually kept outdoors and are particularly at risk if near woodland, as wood pigeons (Columba palamuis) and feral pigeons are often heavily infected – as are wild birds such as starlings.
Cause Mycobacterium avium.
Signs Dullness, loss of appetite, lethargy and a tendency to squat in a sleeping position with the head tucked under one wing.
Body temperature may reach 44° C (112° F).
The comb and wattles may become almost purple, and swollen because of oedema. In young birds, there is muscle wastage and the comb may become pale in colour. The disease progresses slowly. It used to be referred to by pigeon fanciers as ‘going light’.
Infection occurs following ingestion of food and water contaminated by the droppings of infected birds. Infection has been found in eagles at post-mortem examination, presumably from consumption of infected prey.
Cage birds can also be affected. Chronic wasting disease can be seen in the intestinal form and cutaneous mycobacteriosis has been reported in parrots. The public health significance of mycobacteriosis in companion animals must be addressed with great care.
Cattle Avian tuberculosis rarely causes progressive disease, but the presence of avian TB bacteria will affect the interpretation of the tuberculin test. This infection must be differentiated from Mycobacterium bovis infection by using avian tuberculin as well as mammalian in the test. (See TUBERCULIN TEST.)
Sheep Avian tuberculosis can cause miliary tuberculosis in sheep.
Pigs A non-progressive infection is often found in lymph nodes at slaughter. The source of infection in housed pigs can be the use of peat as litter. M. avium survives in peat for a considerable period.
Post-Mortem Emaciation is usually well marked, and whitish-yellow nodules are present in the liver and spleen; also the intestines. The lungs are rarely affected in avian tuberculosis. In birds that have died suddenly, death is often found to be due to rupture of the liver which, when affected with tuberculosis, is often enlarged and friable.
With valuable pedigree birds the intradermal tuberculin test may be employed, but before applying this test all birds should be examined and all thin birds destroyed, since those in the advanced stages of the disease may fail to react. Birds which pass the test should be put in clean houses on fresh ground.
(See also DISPOSAL OF CARCASES.)
The husbandry, keeping, breeding and rearing of birds, especially in cages and aviaries.
A protein in raw egg white that neutralises the B-vitamin biotin.
An antibiotic feed additive formerly used as a growth promoter in pigs and poultry. Its use in the EU was prohibited in 2006.
The name given to the VIRUS that infects birds. Almost all species are susceptible (except cockatiels – Nympicus hollandicus). Lesions follow damage to the skin (often by ECTOPARASITES); classically, they form papules and pustules. In some species the lesions become fibrous, proliferative and become almost neoplastic in appearance. Sometimes lesions spontaneously regress but in canaries (Serinus species) they can fatally involve the respiratory system. Treatment involves topical antiseptics and antibiotics to control secondary infection and improved husbandry, especially nutrition, to encourage immunity development. The problem is being increasingly seen in British wild birds and appears to be spread at the bird table. Avipox is used in the manufacture of some vaccines.
Avitaminosis is a term used to describe conditions produced by a deficiency or lack of a vitamin in the food. Thus ‘avitaminosis A’ means a deficiency of vitamin A. (See VITAMINS.)
Persea americana fed to goats and sheep, during a drought in South Africa, caused death within a few days from heart disease.
An American review in dogs and cats over a one-year period showed that grass awns comprised 61 per cent of all foreign body cases. The most common site is the ear canal (51 per cent), and rupture of the tympanum has been an occasional sequel. Other sites are the interdigital skin in dogs - which again is quite common - and the conjunctiva, nose and lumbar region. Perforation of a bronchus leads to necrosis of a lung lobe. In cats, chronic cystitis has been caused by awns in the bladder.
Derived from an axis. Often used with bones. See Opposite ABAXIAL.
Axilla is the anatomical name for the region between the humerus and the chest wall, which corresponds to the armpit in the human being.
The second cervical vertebra or epistropheus upon which the atlas or first vertebra is placed. It includes an odontoid peg which allows the axis to rotate on the axis. See ATLAS.
Axolotl (Ambystoma mexicanum) is the ‘tadpole’ stage of a mole salamander (Ambystomatidae) that remains and breeds at this stage, unless the environment alters in some way so that it develops into the Mexican mole salamander. Axolotyls are occasionally kept as pets but, more recently, they have been kept for the production of fertile eggs for the use in screening compounds for teratogenicity.
(See NERVES.)
A disease of axons.
A breed of dairy cow originating from Scotland. It has a red-brown and white coat. It milks well but produces less volume than the FRIESIAN or the HOLSTEIN. It is smaller than either of these two breeds and relatively fine-boned. Its male calves are of limited value for producing beef. It is susceptible to vulval squamous cell carcinoma in Kenya.
An organo-phosphorus compound used for the control of mature and pre-adult and adult stages of sea lice (Lepeophtheirus salmonis and Caligus spp.) in farmed salmon. Treatment involves raising the salmon cage until it is at a depth of about 2 m (6 ½ ft) at the centre and then enclose the cage in a tarpaulin so that it is totally leakproof. Oxygen is added to the system followed immediately by the drug. The tarpaulin is removed after 30 to 60 minutes. Persons operating the system have to do so under the terms set out in the Control of Substances Hazardous to Health Regulations 1999.
A neuroleptic drug used in pigs for reducing aggression and preventing fighting. It is used as a sedative when pigs are being transported (not for slaughter, as it has a 10-day withdrawal period) and may be given as premedication before administering an anaesthetic or to reduce excitement when assistance at farrowing is required. Its effect may be less reliable in Vietnamese pot-bellied pigs.
It is also used for sedation in ostriches.
The presence of urea and other nitrogenous products in greater concentration than normal in the blood, particularly in paralytic myoglobinuria in horses.
The presence of urea and other nitrogenous products in greater concentration than normal in the urine.
(See EQUINE RHABDOMYOLYSIS.)