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BRYAN-COLLEGE STATION — For many horse owners, breeding is an opportunity to shape the next generation — whether by continuing a trusted mare’s legacy or raising a foal with carefully selected traits like temperament, athletic ability, or pedigree.
While it can be a deeply rewarding experience, breeding requires a long-term commitment and thoughtful preparation to help ensure a healthy outcome for both mare and foal.
Dr. Mariah Pearson, a clinical assistant professor at the Texas A&M College of Veterinary Medicine and Biomedical Sciences, emphasizes the importance of preparation and offers valuable insights into the mare breeding process.
Starting on the right hoof Because breeding season typically begins in early spring, planning should start in the fall to allow time for health evaluations, reproductive screenings, discussions with your veterinarian, and to ensure your mare is fully prepared.
The first step is to have a trusted veterinarian perform a breeding soundness exam, an assessment that evaluates a mare’s overall health and reproductive condition through a physical exam, palpation, ultrasound, and sometimes testing for potential infections in the uterus.
“Mares need to be systemically healthy first,” Pearson said. “That means no metabolic diseases, no severe lameness, and a sound body condition.”
Without the breeding soundness exam, underlying problems may go unnoticed and lead to serious complications in the future.
“A lot of times, people love their horse so much they want her to have a baby — but they don’t think about all the potential problems,” Pearson said. “You could spend all this money and get your mare pregnant, and then she has trouble giving birth, putting your mare’s life at risk.”
Even manageable conditions can worsen under the physical demands of pregnancy.
“Getting pregnant puts weight on the mare. If she has laminitis or tendon problems, the lameness could get worse,” Pearson said.
If your mare is not a candidate for pregnancy, embryo transfer or other alternatives may be worth discussing with your veterinarian.
‘Foal’ proof planning
Another important step in preparing your mare for breeding is discussing genetic testing.
“Certain breeds have known genetic problems,” Pearson said. “If your mare carries a genetic disorder, breeding her could pass that on.”
Timing also plays a major role. Mares are seasonally polyestrous, meaning they cycle during the months that have the longest amount of daylight. Most begin cycling naturally in spring, but artificial lighting can stimulate earlier cycles.
“I love to see mares early in their cycle — ideally in January if they are under lights or in March and April if not,” Pearson said. “The challenge comes during the transition period, when mares may act like they’re in heat but have not ovulated yet.”
Age matters, too. Younger mares tend to conceive more easily and carry foals with fewer complications.
“The quality of a mare’s eggs declines with time because she’s born with all she’ll ever have,” Pearson said. “Breeding younger mares generally gives better results, especially if you want her to carry the foal herself rather than having a recipient mare.”
Bridling your budget
Breeding is not only physically demanding — it also can be a significant financial responsibility. Even if your mare is generally healthy, complications can make it more expensive than planned.
“Getting a mare ready to breed — even a young, healthy one — can cost thousands of dollars,” Pearson said. “You might need multiple exams or antibiotics for uterine infections before conception even happens.”
After breeding, your mare will need veterinary checkups at key milestones such as:
• 14 days post-ovulation to confirm pregnancy
• 25 to 28 days to check for a heartbeat
• 35 to 45 days to make sure the pregnancy is progressing
• Throughout gestation, your veterinarian may also recommend:
• Vaccinations for equine herpesvirus at five, seven, and nine months
• Fetal sexing, typically performed between 63 and 73 days or 100 and 120 days Breeding a mare is a big decision — medically, emotionally, and financially. Horse owners should carefully consider not only their mare’s physical health and genetic history but also their own readiness for the long-term commitment involved.
If you are thinking about breeding, be sure to talk with your veterinarian early to develop a plan that is right for you and your mare.
“Breeding isn’t for the faint of heart,” Pearson said. “It’s important to understand the risks and responsibilities before you start. That way, you’re prepared — not just for the foal, but for everything that comes with it.”
Pasture Talk is a service of the College of Veterinary Medicine & Biomedical Sciences, Texas A&M University. Stories can be viewed on the web at vetmed.tamu.edu/ news/tag/pasture-talk/. To sign up for the Pasture Talk mailing list or suggest a future topic, please email [email protected].
