Breeding Soundness Examinations

When introducing a new mare to the broodmare group or bringing in a new stallion for breeding purposes, it’s crucial to consider factors beyond just bloodlines, conformation, and pedigree.

For non-pregnant mares, investing in a breeding soundness exam (BSE) is highly advisable. This examination can prevent unnecessary time and financial resources spent on attempts to impregnate a mare with reproductive issues. Similarly, mares that failed to conceive or carry a foal to term in the previous breeding season should also undergo a BSE.

Stallions, too, should undergo a BSE before the breeding season begins. Waiting until the breeding season is underway and finding mares not pregnant is not a prudent approach. Each BSE should be tailored to the individual mare or stallion and the specific circumstances presented. It’s important to note that BSE results cannot guarantee the fertility of a mare or stallion but can only assess their potential fertility at the time of examination.

Mare Examination

The BSE for a mare starts with a comprehensive review of her history. Knowing the mare’s previous pregnancies, any years without live foals, and details of past breeding management programs is essential. The physical exam includes evaluating the mare’s overall condition, considering factors such as body weight and dental health, which directly impacts body condition. Proper weight and nutrition significantly contribute to a mare’s likelihood of becoming pregnant.

Maintaining proper body condition is critical for a mare to conceive and maintain a pregnancy. Studies show that mares with a body condition score below 5 at foaling have lower pregnancy rates. The external genitalia and mammary glands are examined, and a thorough palpation and ultrasound assess the uterus and ovaries. The vaginal speculum exam checks for adhesions, urine pooling, and varicose veins.

A uterine culture and cytology are performed to identify bacterial or fungal infections. When combined with physical exam findings, these results allow for an intelligent evaluation of the mare’s potential to maintain a full-term pregnancy or produce an embryo for transfer. The data guide the development of a treatment plan for mares with uterine infections, which may include antibiotic therapy, Caslick surgery, acupuncture, and hormonal therapy.

Stallion Examination

The stallion’s BSE begins with a detailed history, including previous breeding management programs, medications, and breeding performance. Evaluating the stallion’s overall health and body condition is crucial. The examination includes assessment of the genitalia, semen collection, and culture samples. An equine viral arteritis test is conducted, and cultures identify any bacteria affecting fertility.

Libido and mounting behavior are evaluated, and the penis is examined for abnormalities or injuries. Testicular size and sperm output are assessed through ultrasonography. Semen evaluation includes color, morphology, volume, concentration, and motility. The BSE also examines the semen’s ability to withstand cooling, freezing, and shipping.

Similar to the mare BSE, the final evaluation considers all test results. While it doesn’t guarantee reproductive abilities, the stallion BSE predicts the stallion’s capacity to impregnate mares, determining how many mares he can breed per day and per season.

While a BSE demands time and financial investment, it proves worthwhile in understanding the reproductive status of both mare and stallion before the breeding season begins. Collaborating with an equine reproductive veterinarian enhances the chances of a successful breeding season.

By Staff writer
Photos courtesy of Lyndsey Lamell Photography