A mare should not be bred on foal heat if she has encountered the following:
e) All of the above
Many breeders will breed their mares during foal heat. Foal heat occurs seven to nine days after foaling and lasts for approximately three to five days. Often, a mare will not display the typical behavioral signs of estrus such as frequent urination or winking of the vulva.
Some breeders may choose to wait a few months after foaling, especially if a mare had difficulties foaling, before rebreeding so that involution of the uterus can take place. Involution of the uterus is when the uterus returns to normal size post-partum. The mare’s uterus usually undergoes complete involution 3 – 4 weeks after foaling. Other factors that would caution against breeding at foal heat are a retained placenta, which subjects a mare to possible infection tears in the uterus lining, or a low body condition score (under 5).
To learn more about breeding the mare, read the November 2009 e-Tips article Breeding the Mare: Factors That Can Influence Conception Rates and watch the webcast by Dr. Kathy Anderson, Why Won’t My My Mare Get Pregnant?