Teasing is essential to detect when a broodmare is in estrus, but it's no easy feat due to the size and power of the animals involved. Safety should be top priority–to avoid injury to horses and people.

Teasing is particularly useful on farms with more than a dozen mares, according to Ahmed Tibary, DVM, PhD, Dipl. ACT, professor of theriogenology in the department of veterinary clinical sciences at Washington State University.

"You are then looking at two options," he says. "During breeding season you'd have the vet come every other day to scan mares, or use a teasing stallion to reduce the number of veterinary examinations."

If the farm is using artificial insemination, Tibary suggests it might be better to have a veterinarian evaluate the mare's cycle by using ultrasonography rather than rely on a teaser. Teasing stimulates the mare in readiness for breeding due to release of oxytocin (a hormone that stimulates milk let-down and causes uterine contractions) in her body, but this also can be accomplished by hormonal treatment, he says