PRODUCTIVE PERIOD IN BROOD MARES

The most fertile period in the mare's life is usually at four to twelve years of age. In exceptional cases this period may begin at an earlier age and last longer. Occasionally a filly will breed freely at two years of age, thus foaling her first colt at three; and not unfrequently mares breed when past twenty years of age.

Breeding two-years-old fillies
The advisability of breeding a two-years-old filly depends on at least three important factors: First, the breed: Horses of draft breeding mature much earlier than do lighter and more active breeds, so that a draft filly of two years is often as forward as a trotting or running filly at three years of age. Secondly, the individual animals: Individuals differ considerably in attaining maturity. Usually a smoothly turned, neat, and well finished filly makes its growth earlier than does a rougher, more vigorous individual. Feeding and care also have much to do with the early maturity of the filly; one that is kept growing continuously will mature earlier than one that is imperfectly cared for and that receives a setback each winter. Thirdly, the object sought: If the breeder is endeavoring to improve the strain, he should never attempt to breed a two-years-old filly. On the other hand, when draft horses are wanted merely for marketing there is no reason why fillies cannot be bred at two years of age, provided they are mature and have been well grown, and their owner is willing to feed and care for them properly during their pregnancy. Nor is there any reason why they should not be bred each year thereafter. They should not be put to work, however, until past three years of age.

Breeding aged mares
At about twelve years the reproductive powers of some draft mares begin to wane, although many mares are reliable breeders to about fifteen years, especially if they have been bred continuously from their maturity. Above this age it is rarely profitable to keep them for breeding. Perhaps it is best to dispose of draft brood mares at ten or twelve years of age unless they are exceptionally good breeders, in which case they should be kept as long as they will breed.

All the information on Practical Horse Breeding is gathered here for your convenience:

PRACTICAL HORSE BREEDING