How many mares can I breed to my stallion?

When artificial insemination is used, 10 mares per day may be bred by a stallion that produces good-quality semen. Mares only need to be bred every other day as spermatozoa survive 48 hours or longer in the mare’s reproductive tract. Therefore, the use of A.I. will allow for every other day collection from the stallion. Collection every other day will produce higher quality semen longer without behavior problems. In a hand–mating situation, the following table provides the number of mares a stallion can service during the breeding season:

Age No. of Mares/Breeding Season
2 * 6 to 10
3 * 10 to 15
Mature 50 to 60
20-25 30 to 40

* dependent on testicle size