A 200-watt lightbulb in a mare's stall is all that's needed to get her brain thinking it's late Spring. The most successful formula is 16 hours of light to eight hours of dark. A change in behavior can be seen after 30 to 60 days, with ovulation occurring 60 to 90 days after the lighting program is begun. A side effect to putting mares under lights in the late fall is early shedding or no winter hair coat at all, since the mare's brain thinks warmer temperatures are on the way. Another method of controlling ovulation is through drugs, using a synthetic form of progesterone.
Progesterone is a naturally occurring chemical important to the estrous cycle in mares.
The use of artificial progesterone can fool a mare into thinking it's time to ovulate, no matter what the time of the year. Usually, lights and artificial progesterone are used in concert for the best results. As always, consult with your local veterinarian. Please read our Privacy Policy . Advertise with us .