Because the length of daylight triggers the mare's estrous cycles, owners can get a jump on the season and induce cycling earlier in the year by putting the mare under artificial lights. Says Dale Paccamonti, DVM, MS, Dipl. Starting in November might even be better. It's important to provide light of sufficient intensity. Hold the camera like you're taking a picture at the level of the mare's eye.
Some experts advocate providing artificial lighting at the end of the natural daylight.
Other experts, says Blanchard, feel it is best to add equal increments of light in both the morning and evening to get the best response to artificial lighting. Once started, the lighting schedule must be strictly maintained. We have noted this problem in some show mares that are blanketed and lighted in the winter to keep their hair coats short. Sometimes the owner stops the lighting program when spring begins and warmer days arrive, and the mare enters a period of anestrus early even though it is only May or June. The month that occurs will vary according to the latitude.