How do I tell when my mare is ready to breed?

A mare will show signs of heat (sexual acceptance of the stallion) about four to seven days of her approximately 21-day-long cycle. In between the heat periods, she is not receptive to a stallion. To check this, you need to tease her with a stallion, something that stallion owners will do as a daily or every-other-day routine to mares. A mare will urinate, swat, lift her tail, and show behavior consistent with receptivity to the stallion when she is in …