Management for Early Breeding - Lights
For many equine disciplines, foals born early in the calendar year have an advantage. Because mares must be bred in February to produce January foals, these mares must be tricked into normal estrous cycles.The most reliable method of managing mares to be bred early in the season is to increase the light exposure by increasing the light added at the end of daylight. The type of light the mares are exposed to is not important but you should be able to read in all corners of the stall or paddock (15 foot candles minimum). It takes 60-90 days from an increase to 16 hours of light (8 hours of dark) until the first ovulation that is associated with a estrus behavior. Starting mares on lights on December 1 will result in the first ovulation with estrus from Feb 1 to March 1. The graphs below depict the behavior of 4 mares in response to a lighting increase to 16 hours on Dec 1. Notice the difference in the transitional response in the mares. Normal cycles began to appear around February 1. Note that there is some missing data in each graph as we did not always have someone here who could check for estrus.
