Preparing for Equine Breeding Season – Skillman Veterinary Services, Indianapolis, Indiana

Mares are seasonal breeders that are influenced by light exposure. If you are aiming for a foal in March 2027, begin your lighting program in the beginning of December.

Start 60 to 70 days before the intended breeding date for the best results.

Managing their light schedule can help bring them into estrus earlier in the year, which is an important factor in planned breeding programs.

Light schedule for a breeding mare:

6:00 AM to 10:00 PM – Light exposure (natural daylight plus artificial lights)

10:00 PM to 6:00 AM – Darkness (8 hours uninterrupted)

Use a timer to turn lights on and off automatically. Mares respond best to 16 hours of light followed by 8 hours of darkness. Leaving lights on continuously is less effective because mares need a period of darkness.

Light intensity should be at least 10 foot-candles, or about 100 lux. A 100-200 watt incandescent bulb or a fluorescent light is usually sufficient for a 12 x 12 foot stall.