How to do it...

To implement this recipe, do the following:

Create the following column in the R05_Table table:

Counter = 
    VAR __Table = 
        ADDCOLUMNS(
            FILTER(
                'R05_Table',
                'R05_Table'[Animal] = EARLIER('R05_Table'[Animal]) && 
                    'R05_Table'[Index] < EARLIER('R05_Table'[Index])
            ),
            "__diff",
            [Index] - 
                MAXX(
                    FILTER(
                        ALL('R05_Table'),
                        'R05_Table'[Index]<EARLIER('R05_Table'[Index]) && 
                            'R05_Table'[Animal]=EARLIER('R05_Table'[Animal])
                    ),
                    [Index]
                )
        ) 
    VAR __Max = MAXX(__Table,[Index])
    VAR __MaxStart = 
        MAXX(
            FILTER(__Table,[__diff]>1),
            [Index]
        )
    VAR __Table2 = FILTER(__Table,[Index]>=__MaxStart) 
RETURN 
    IF(
        ISBLANK(__Max),
        1,
        IF(
            __Max=[Index]-1,
            COUNTROWS(__Table2)+1,
            1
        )
    )