Few scenes are as beautiful as a horse grazing on lush, green, and well-managed pasture. Unfortunately, the typical horse pasture is horribly mismanaged, is terribly overgrazed, and contributes very little to the nutrition of the horses grazing on it. With proper management, though, pasture has the ability to greatly reduce the cost and increase the enjoyment of horse ownership, as well as improve horse health and well-being.
It is important to have realistic expectations of yield per acre and an accurate estimate of acreage to determine a horse pasture’s carrying capacity. There are biological limits to how much vegetation can be produced on an acre. Moisture is often the most limiting factor in pasture growth. The eastern United States usually receives more than 30 inches of annual rainfall, but in the western Plains and Mountain areas there may be less than 15. The table below gives a rough guideline for reasonable stocking rates for the usual 5-month pasture season, adjusted for rainfall.
Note that these recommendations are likely much larger acreages per horse than is often recommended for horse pasture in the more humid rain-fed areas of the eastern United States. The “one acre per horse” guideline that is often cited may occasionally be valid in Iowa or Kentucky, but not Kansas or Nebraska, and definitely not eastern Colorado. If the acreage is hard to estimate, an acre is 43,560 square feet, or approximately the size of a football field. Measure the length and width in feet, multiply, and divide the result by 43,560 to get the acreage.
Probably no other domestic animal, with the exception of swine, has more potential to destroy a pasture than the horse. Because of the equine tooth structure, horses are capable of biting grass almost to ground level and will do so if allowed. No grass will thrive under this form of grazing, and most will not even survive. It does absolutely no good to plant the finest pasture species and then fail to control the grazing pressure and kill the pasture.
It is your job as a pasture manager to prevent this form of grazing. Plants grow via photosynthesis, and it takes leaf area to perform this task. When sunlight strikes bare soil, it means that sunlight is NOT being used to grow feed and is wasted potential feed. It should be a primary goal during the growing season never to have bare soil.
In fact, most pasture grasses should be maintained with a minimum stubble height of 4 inches throughout the entire season (refer to chapter 2 for more information on residual forage height to be left after a grazing episode, by species of forage). If horses have continuous, uncontrolled access to a pasture, minimum stubble height cannot be maintained. Even with plenty of acreage allowed, horses will return to eat the tender regrowth of plants they have previously grazed and ignore the tall, rank growth of adjacent ungrazed plants inches away.
Rotational grazing is a powerful tool to maintain healthy pastures with horses. (Note: Be sure to read the chapters 6 and 7, on stocking rate and grazing management.) Pastures should be subdivided into at least four paddocks; more paddocks are more advantageous. The easiest way to divide pastures is with electric fences radiating out from a water source into the pasture. Paddocks do not need to be the same size to be effective. These paddocks can be further subdivided with polybraid wires on reels and step-in fence posts to allow moves as frequent as daily.
Moving daily is far more efficient than less frequent moves. There should be at least 8 inches of growth in a paddock upon initial entry. When the grass is grazed down to 4 inches, move to the next paddock and repeat the process. Return back to a paddock once regrowth reaches 8 inches or more.
Now here is the important part: if regrowth has not reached a minimum of 8 inches, lock animals into a pen and feed hay rather than pasture. You can and probably should supplement pasture with hay, but NEVER use hay as a means to allow horses to stay on a pasture after the stubble height drops below 4 inches. Hay fed as a supplement during the growing season should be in an adjacent pen, rather than in the pasture itself.
The two most common mistakes made by those beginning rotational grazing are: (1) rotational overgrazing; that is, trying to have animals eat every last bit of the grass before leaving a paddock; (2) trying to base movement dates on the calendar rather than on grass growth. It is very common among beginning rotational graziers, many of whom have a Monday-through-Friday full-time job, to tell themselves that they will have four paddocks and they will simply move every Saturday when they have time, and each paddock will get grazed once a month. This only works when each paddock grows exactly a week’s worth of feed at a time, which seldom if ever occurs. It is common for people on the “weekly move” plan to visit their pasture on Saturday only to find that during this time the grass has been grazed to bare dirt.
In one study conducted in Missouri, grass grazed to 4-inch stubble height took 30 days to regrow to a 12-inch height, while grass grazed to a 2-inch stubble height took 45 days to regrow to a 12-inch height. The difference in a 4-inch stubble height and a 2-inch stubble height is often just one additional day too long in a paddock. Moving on Saturday when the move should have been done on Friday may have gained one day’s grazing on this rotation but lost 2 full weeks of regrowth that will need to be made up at some point.
If you have too many horses for your pasture acreage, the obvious solution is to either expand acreage or reduce numbers, but sometimes there is insufficient area to grow enough feed for even one horse, and it is hard to create a fraction of a horse. All too often the horses are fed hay as a supplement to a pasture that is of insufficient area, but the horses are given unrestricted access to the pasture and the horses eat every blade of grass in preference to the hay and eventually destroy the pasture.
It is possible with creativity and planning to have a horse on a small acreage and still gain value from pasture. The practice of time-limit grazing keeps the horses locked in a pen adjacent to the pasture and allows free-choice hay, letting them out to graze for roughly an hour a day. This concept can be combined (and preferably so) with a rotational grazing scheme. This creates a twice-daily time commitment (once to open the gate, and another to chase them back in and close the gate), but even this can be managed with creativity.
A device called a Batt latch, works on a timer and allows an owner to be absent when the gate needs to be opened. Another innovation, the fish-trap gate, uses a barrier that swings only one way, allowing animals into the pen to get water after grazing but preventing their return to the pasture.
Since horses can graze so close to the ground, plants suited for horse pasture should be tolerant of severe grazing. This usually requires growing points and leaf placement close to the soil surface. With good grazing management (rotational grazing with adequate residual left after each grazing) the list of suitable plants for horse pasture expands greatly. More than any other domestic animal, horses prefer grasses over other plants. While grasses form the basis of a good pasture, legumes can be a valuable addition because of their ability to fix nitrogen and their higher protein content.
Not all grasses are created equal. Warm-season grasses have a completely different physiology from that of cool-season grasses, which begin growth in early April, form seedheads by late May, grow very little in the heat of summer, and then have a growth period in the fall with sufficient moisture. This is a much longer growing season than warm-season grasses have.
Cool-season grasses require more moisture and more nitrogen to produce a pound of forage than do warm-season grasses. Despite their poorer water use efficiency, some cool-season grasses can tolerate drought simply by going dormant during the summer. This aids survivability but obviously reduces forage availability in the summer.
In a fish-trap gate, the spring stretches to allow an animal to pass through but snaps back to keep it from returning.
Cool-season grasses require a source of nitrogen in order to produce well, either fertilizer or an associated legume. At similar stages of growth, cool-season grasses are higher in protein and more digestible than warm-season grasses.
Warm-season grasses begin growth in early May, begin to form seedheads in August, and go dormant around first frost in the fall. Despite their lower quality at similar growth stages compared to cool-season grasses, they usually offer higher animal performance in the summer than cool-season grasses because they are at an earlier stage of maturity than cool-season grasses.
Native prairie in the eastern part of Kansas and Nebraska typically consists of big bluestem, Indiangrass, little bluestem, switchgrass, and sideoats grama. In the western part of these states, it is primarily buffalograss and blue grama, and the central part is a mosaic of the two ecotypes. The bluestem prairie is more productive but less tolerant of overgrazing than the buffalograss plains. Buffalograss is tolerant of grazing to a 2-inch stubble, while the bluestem requires a 4-inch stubble.
Usually these grasses are in preexisting stands, but it may be desirable to plant new stands of restored prairie. The drawback to replanting is the usual 2 full years’ establishment period of these grasses prior to first grazing season. This establishment period can be drastically shortened by inoculating seed with mycorrhizal fungi prior to planting. In a new seeding, switchgrass should be omitted, since it is unpalatable to horses.
Suggested tallgrass mixture per acre: 4 pounds big bluestem, 2 pounds each Indiangrass, little bluestem, and sideoats grama, planted from January through May
Suggested shortgrass mixture per acre: 1 pound blue grama, 2 pounds buffalograss, and 3 pounds sideoats grama, planted from January through May
Bermudagrass is an introduced warm-season grass of lower quality than native grasses, but with more yield potential and very good tolerance of hard grazing. It also establishes quicker than native grasses. To realize the higher yield potential, though, it requires nitrogen fertilization. Bermudagrass is adapted to areas receiving more than 25 inches of moisture and south of Interstate 70.
Planting: Suggested seeding rate is 10 pounds per acre planted in May. Where adapted and sprigging equipment is available, sprigged varieties are more productive than seeded ones. Alfalfa can be interseeded into bermudagrass in the fall to make a very productive pasture.
Eastern gamagrass is a native grass with exceptional yield potential and good quality. However, the seed is quite expensive, is slow to establish, and requires very careful grazing management (12-inch stubble heights remaining after each grazing). It responds well to irrigation and fertility.
Planting: Suggested seeding rate is 10 pounds of pure live seed per acre planted in January or February. After the first growing season, legumes may be interseeded.
Tall fescue is probably the best-suited cool-season grass for horses, but only if endophyte-free, or better yet, “friendly endophyte” or “novel endophyte,” varieties are used. The predominant fescue variety Kentucky 31 (K31 for short) is infected with a seed-borne endophyte (meaning it lives inside the plant) fungus that causes the plant to produce toxins to which horses are particularly sensitive. Horses on K31 fescue seldom perform satisfactorily: pregnant mares often abort, and if they do produce a foal, they fail to milk. Most “turf type” fescues also contain this fungus.
Endophyte-free varieties will produce animal performance far superior to that on K31. The fungus is not all bad, however, as it somehow causes the plant to be more heat and drought tolerant. This is why the friendly endophyte fescues (or novel endophyte or nontoxic endophyte, as they are sometimes called) were developed. They combine the heat and drought tolerance of K31 with the superior animal performance of the endophyte-free varieties.
Tall fescue is very tolerant of hard grazing (and it also responds well to the recommended 4-inch stubble minimum) and has the unique ability to retain good grazing quality well into the winter if left ungrazed in the fall.
Planting: In a pure stand, plant 20 pounds per acre either from March 15 to April 15, or August 15 to September 15. Fescue is a bunchgrass but does form solid turf.
Timothy is a grass that is often associated with horses but has little value as horse pasture. While it makes good-quality hay, it is intolerant of close grazing, and does not tolerate heat or drought well.
Kentucky bluegrass is another grass often associated with horses, because it is very tolerant of close grazing. Despite this, it is low yielding and has very poor heat and drought tolerance and thus should not compose a high percentage of a pasture mixture unless planted in an area of consistent moisture. In more arid areas, it usually dies out in the summer and recovers with fall rains.
Planting: Because it does have such good tolerance of horse grazing, it is a valuable addition to a mixture at 1 to 2 pounds per acre. It is a sod former and thickens over time.
Smooth bromegrass is one of the more drought-tolerant cool-season grasses and is very palatable to horses. Despite its ability to survive on lower rainfall than other cool-season grasses, it achieves this feat with a high level of summer dormancy and furnishes very little summer forage. It is also unproductive when grazed closely but recovers well when properly grazed. It should be grazed to maintain a 6-inch residual stubble height. It is a sod former, and stands thicken over time.
Planting: In a pure stand, it should be seeded at 20 pounds per acre from March 15 through April 15, or August 15 through September 15.
Western wheatgrass is a native cool-season grass that is one of the most drought-tolerant cool-season grasses, but it is low yielding and of relatively poor quality. It has the most utility in western states where other cool-season grasses do not thrive. Even so, it is best used in a mixture where it has the primary value of being the sole cool-season grass to survive when other grasses of better yield and quality die off during prolonged drought. It forms a loose sod and spreads well.
Planting: A pure-stand rate is 10 pounds per acre.
Other wheatgrasses perform roles similar to western wheatgrass, though they are all somewhat different. Intermediate wheatgrass is more productive and often seeded. Do realize, however, that it is a bunchgrass and is much taller growing and less tolerant of close grazing than western wheatgrass. Crested wheatgrass is a bunchgrass that is very tolerant of drought and close grazing, making it a valuable horse pasture component. It is only productive, though, in the early part of the grazing season. It is also allelopathic (toxic to other plants) and tends to form undesirable monocultures.
Orchardgrass is a bunch grass that is productive and palatable to horses. It is usually short-lived and should be allowed to occasionally reseed. It is not as tolerant of heat and drought as brome or fescue. It is of most value in combination with longer-lived grasses.
Planting: A pure-stand rate is 12 pounds an acre. It is very compatible with most legumes.
Meadow brome is a bunch grass that has far better regrowth and fall production than smooth brome, which it resembles. It is probably underutilized in pasture plantings but is best used in combination with sod formers.
Planting: A pure-stand rate is 20 pounds per acre.
Mixtures of cool-season grasses can combine positive traits of several grasses into one pasture. Mixtures are usually higher yielding and more resilient than a monoculture. They also allow for survival of the fittest, in which species sort out by suitability to soil type and grazing management. To create a mix, just take the pure-stand seeding rate and use the same percentage of that rate as you desire in the pasture composition.
Alfalfa is by far the most productive legume, and since horses do not bloat like cattle, it has more utility in horse pastures than in cattle pastures. Alfalfa must be rotational grazed, with rest periods long enough to allow blooming to occur before each grazing period. It will rapidly disappear under continuous grazing. It is very high in nutritional value, and its ability to fix large amounts of nitrogen is a great boost to pasture productivity. In a blend with grasses, it can be planted at up to 6 pounds per acre at the same time as the grasses. It is compatible with most grasses.
Red clover ranks second to alfalfa in both productivity and nitrogen fixation. It combines well with cool-season grasses but is too competitive to warm-season grasses. It is one of the easiest legumes to establish in an existing grass stand. Red clover requires rotational grazing in order to thrive. Plants usually live only 3 years, so it should be allowed to occasionally reseed, requiring at least a 60-day rest period. Plants can be grazed after seed maturity (when flowers have turned brown), and seedlings will develop in manure to renew the stand. Occasionally red clover plants get infected with a black mold that is mildly toxic to horses (the toxic agent is called slaframine) and causes slobbering and an unthrifty appearance, but this usually occurs only in the more humid eastern United States.
Planting: In a blend with grasses, it can be planted at 5 to 10 pounds per acre by broadcasting seed in January or February into existing grass, or drilling at the time of seeding the grasses.
White (Dutch) clover is a legume of low yield but exceptional quality. It is somewhat unique among legumes in that it is very tolerant of hard grazing. It also spreads by stolons (runners) and thus thickens over time, even under hard grazing. It is the only common legume tolerant of hard, continuous grazing. It has poor tolerance of heat and drought, and often dies out during summer but recovers with rain. It is compatible with both cool- and warm-season grasses.
Planting: In a mixture, plant at 1 to 2 pounds per acre. It can be broadcast into existing stands in January or February or planted at the same time as cool-season grasses.
Ladino clover is a giant strain of white clover and is roughly three times as productive but shares the poor tolerance of heat and drought of white clover. Although higher yielding, it does not recover as well after drought as Dutch white does. There are also hybrids of Dutch white type and Ladino type clovers, called “intermediate” white clovers, that tend to be more heat and drought tolerant than either parent. Example varieties include Louisiana S-1, Durana, and Renovation.
Pearl millet is a highly productive summer annual grass that can furnish abundant grazing in July and August.
Planting: It should be planted after soil temperatures reach 60°F (15.5°C) in spring at a rate of 15 pounds per acre and can furnish grazing within 45 days after planting. It should be grazed to leave a residual stubble height of at least 8 inches.
Browntop millet is a good horse pasture, although not as productive as pearl millet.
Planting: It should be seeded at 20 pounds per acre after soil temperatures exceed 60°F (15.5°C).
Crabgrass is a surprisingly good horse pasture in late summer, both in terms of productivity and nutrition. It can be broadcast seeded into existing cool-season pastures to improve summer productivity or seeded into bare ground by itself or in mixture with other summer annuals as a dedicated summer pasture.
Planting: In a pure stand, it should be seeded at 6 pounds per acre after soil temperatures reach 60°F (15.5°C) in spring.
Teff is another summer annual grass that is most often used as a rapid-drying, high-quality hay but can also be utilized as late-summer pasture.
Planting: It should be planted at 6 pounds per acre after soil temperatures reach 60°F (15.5°C) in spring. It is important to place teff seed no more than 1⁄4 inch deep, preferably at 1/16 inch deep. It can be broadcast and harrowed in effectively.
Wheat, rye, triticale, and winter barley are all productive winter annuals for horses and can provide late-fall and early-spring pasture. They should be seeded at 60 to 120 pounds per acre in late August to September. Wheat is the least productive of these and is susceptible to diseases when planted this early. Wheat grown as a grain crop can often furnish incidental grazing, though, without harm to grain yield if animals are removed prior to jointing stage of the wheat.
Endophyte-infected tall fescue (Kentucky 31) can cause myriad problems for horses, including abortion, retained placentas, and failure to produce milk. Endophyte-free fescue is safe for horses but may lack persistence. Novel endophyte (a.k.a. friendly endophyte) fescues are as persistent as Kentucky 31 but are safe for horses as well as other livestock.
Sorghums, sudangrass, and sorghum-sudangrass hybrids can contain prussic acid, as well as other toxins, to which horses are very sensitive. Sorghums should not be pastured or fed to horses.
Foxtail (or German) millet contains a compound that causes joint pain in horses. It should not be used for either hay or pasture for horses.
Hairy vetch, crimson clover, and arrowleaf clover are all unpalatable to horses. Hairy vetch contains horse toxins, and crimson clover can cause hairballs in the stomach and colic.
Illinois bundleflower is a native legume often planted in native grass blends. Although it is not toxic to horses, it is very unpalatable to them.
Ryegrass (either perennial or annual) is of exceptional quality but is actually too high in sugar content for horses and can cause founder issues. Ryegrass hay, however, has usually lost enough of its sugar content during curing to be safe for horses.
Alsike clover contains compounds toxic to horses.
Sweetclover seed is toxic to horses, although horses usually avoid eating sweetclover after seed set due to its coarse nature.
Switchgrass is both unpalatable and mildly toxic to horses. As long as adequate forage is available on native pastures containing switchgrass, it should be no problem, but horses may consume it if no other forage is available.
