Successful mare care during foaling season requires strategic preparation months in advance, including vaccination schedules, nutritional adjustments, heat cycle monitoring, and creating biosecure environments. Whether managing an open mare or a pregnant one, proper planning significantly improves conception and foal health.
Key Takeaways
- Begin supplemental lighting 60 days before breeding to synchronize heat cycles and optimize fertility.
- Pregnant mares require tailored vaccination protocols in the final trimester to protect both mare and foal.
- Biosecurity measures during foaling season prevent disease transmission that can compromise breeding success.
- Nutritional management shifts throughout gestation, with the greatest demands occurring in late pregnancy and early lactation.
Preparing the Non-Pregnant (Open) Mare
Preparing an open mare for breeding requires starting well before spring, as her reproductive system responds to environmental cues like daylight. Strategic interventions during the transition from winter anestrus to breeding season can determine first-cover success.
Veterinary Health Checks and Vaccinations
Before breeding season begins, schedule a comprehensive reproductive examination. Your veterinarian will perform a uterine culture and cytology to identify any subclinical infections that may prevent conception or cause early embryonic loss. Addressing these issues before breeding saves time and money. Core vaccinations should be current, with special attention to equine herpesvirus (EHV) and equine viral arteritis (EVA), both of which can cause abortion or infertility. Most breeding farms require EVA testing before allowing outside mares on the property.
Supplemental Lighting
Mares are seasonally polyestrous, meaning their reproductive activity increases as days lengthen. In natural conditions, most mares don’t begin regular cycling until late spring. Supplemental lighting programs trick the mare’s pineal gland into responding as if spring has arrived early. By providing 16 hours of light daily starting 60 to 90 days before your target breeding date, you can advance the breeding season significantly. This doesn’t require expensive equipment. A 200-watt bulb in a 12×12 stall provides adequate illumination when turned on at sunset and programmed to extend the photoperiod.
Heat Cycle
Understanding the mare’s estrous cycle helps you time breeding appropriately. A typical cycle lasts 21 days, with the mare receptive to the stallion for five to seven days during estrus. However, transitional heat periods in early spring can be irregular and prolonged. These transitional cycles often don’t result in ovulation, which is why ultrasound monitoring is valuable. Your veterinarian can track follicular development and predict ovulation within 24 to 48 hours, allowing for precise breeding timing, whether you’re using live cover or artificial insemination.
Methods to Drive Follicular Growth During Transition
When mares experience prolonged transitional periods with small, inconsistent follicles, veterinary intervention can help. Progesterone products like altrenogest (Regu-Mate) can be administered for 10 to 14 days, then withdrawn to synchronize the mare’s cycle. Some veterinarians use gonadotropin-releasing hormone (GnRH) or human chorionic gonadotropin (hCG) to stimulate ovulation once a follicle reaches adequate size. These protocols work best when combined with regular ultrasound monitoring to assess the mare’s response.
Preparing Your Pregnant Mare for Foaling Services
Once your mare is confirmed pregnant, your management focus shifts from conception to maintaining a healthy pregnancy and preparing for a safe delivery. The final 90 days of gestation demand particular attention. This is when the fetus undergoes its most rapid growth and when the mare’s nutritional and health management directly impacts foal viability.
Veterinary Exams
Regular veterinary monitoring throughout pregnancy helps identify potential complications early. Beyond initial pregnancy confirmation at 14 to 16 days, most practitioners recommend ultrasound examinations at 25 to 30 days to confirm heartbeat and again at 45 to 60 days to verify continued viability. During the final trimester, schedule at least one examination to assess the mare’s body condition, mammary development, and overall health. Many veterinarians recommend Caslick’s surgery for mares with poor vulvar conformation to prevent urine pooling and ascending infection before foaling.
Exercise
Moderate exercise throughout pregnancy maintains muscle tone and cardiovascular fitness, both of which contribute to easier deliveries. Pregnant mares can continue their normal work routines through the first two trimesters, though you should avoid activities with high fall risk. During the final trimester, scale back to light exercise, such as hand walking or turnout. Complete rest isn’t beneficial unless medically indicated. Movement promotes healthy circulation, prevents excessive weight gain, and keeps the mare mentally engaged.
Biosecurity Tips
Foaling season coincides with increased disease risk due to concentrated populations of vulnerable newborns. Implement strict biosecurity protocols well before your mare’s due date. Isolate incoming mares for at least two weeks. Disinfect foaling stalls between occupants with products effective against common pathogens such as Salmonella and Rhodococcus equi. Limit visitor access to foaling areas and require hand washing or sanitizing before handling mares or foals. Staff who handle foaling mares shouldn’t simultaneously work with other horses without changing clothes and boots.
Nutrition
The pregnant mare’s nutritional requirements increase dramatically during late gestation. During the final 90 days of pregnancy, the fetus gains approximately 65% of its birth weight. Your mare needs increased protein, energy, and minerals, particularly calcium and phosphorus, for fetal bone development. A quality broodmare feed formulated for late pregnancy typically provides the necessary nutrients. Body condition score should be maintained at 5-6 on a 9-point scale. Underweight mares produce smaller foals with reduced immune function, while overweight mares face an increased risk of dystocia and metabolic complications.
Frequently Asked Questions
When should I start preparing my mare for breeding season?
Begin supplemental lighting programs 60 to 90 days before your target breeding date, typically in December or January for spring breeding. Schedule veterinary examinations and update vaccinations at least 30 days before breeding begins.
What vaccinations does my pregnant mare need before foaling?
Administer equine herpesvirus (EHV) vaccines at months five, seven, and nine of gestation. Give a combination vaccine containing tetanus, Eastern and Western equine encephalomyelitis, West Nile virus, and rabies, 4 to 6 weeks before foaling to maximize antibody transfer to the foal via colostrum.
How do I know when my mare is about to foal?
Watch for mammary gland enlargement, wax formation on teats, vulvar relaxation, and behavioral changes like restlessness or isolation. Most mares foal at night when disturbances are minimal. Foaling typically occurs within 24 to 48 hours after wax appears on the teats, though individual variation exists.
What should I feed my pregnant mare in late gestation?
Feed a broodmare-specific concentrate formulated for late pregnancy, providing approximately 1.5 to 2 pounds per 100 pounds of body weight daily, along with quality hay or pasture. Ensure adequate calcium, phosphorus, and trace minerals to support fetal skeletal development.
Setting Your Mares Up for Foaling Success
Proper mare care during foaling season combines proactive planning with responsive management. From strategic lighting protocols that optimize breeding timing to comprehensive vaccination programs that protect both mare and foal, success depends on attention to detail throughout the reproductive cycle. The investment you make in veterinary care, nutrition, and biosecurity directly influences conception rates, pregnancy outcomes, and foal health.
Whether you’re breeding one mare or managing a large operation, partnering with experienced veterinary professionals provides the expertise and support needed for optimal results. At Brazos Valley Equine Hospital, our team specializes in reproductive services from pre-breeding examinations through foaling support. Contact us to schedule a consultation or discuss your specific breeding program needs. We’re here to help you achieve a successful foaling season.
