When a breeding soundness exam is done on a mare, a veterinarian is trying to identify any reproductive abnormalities known or otherwise before breeding is attempted. By knowing this in advance they can evaluate the mares’ potential to carry a foal to term.
The first thing done is to properly identify the mare being evaluated. Then a thorough history of the mares’ previous reproduction attempts and any other issues they have had. Example-Laminitis.
Some terms that will be assigned or used in describing a mares’ reproductive status are:
- Maiden: Mare that has never been bred by any means
- Open: Mare is not bred currently
- Barren: Mare that has been bred in past season and did not become pregnant
- Pregnant: Mare is carrying a foal currently
- Wet: Mare with a foal on her side
- Geriatric: Mare over 15 years of age
After properly identifying the mare, your veterinarian will then do a physical exam paying particular attention to the mares’ body condition and perineal conformation. Body condition scores are assigned to mares ranging from 1-9. A score of 1 is emaciated and a 9 is morbidly obese. We want mares in the 5-6 range to have them breed well. Slightly higher is still okay but lower is not.
Perineal confirmation is a detail focused on during breeding exams. The vulva is a barrier that must be normally oriented to prevent contamination of the reproductive tract. Mares with poor confirmation are much more likely to have pre-existing infection and uterine scarring making them more difficult to breed successfully. A mare with poor confirmation will likely need a “Caslicks” procedure done once settled. This will help keep her reproductive tract from becoming contaminated by feces possibly losing her pregnancy.
The next part of the BSE of your mare is palpation and ultrasound of the reproductive tract. With this the ovarian horns and uterine body are felt and visualized for abnormalities. But, also to determine the stage of their cycle.
Next, a vaginal exam is done using a speculum and the cervix is digitally palpated. Again, looking for abnormalities like urine pooling, cervical lacerations, or a persistent hymen. All these things are noted to cause issues when breeding. Some can be easily resolved, and some cannot.
The last part of the BSE usually done is Culture, Cytology and Biopsy of the uterus. These last three items are very valuable especially for Geriatric and Maidens. Mares need a healthy, clean uterine environment to give them their best chance to carry a foal to term. The culture tells us if the uterus is clear from infection. The Cytology tells us the cell types present. The biopsy tells us if the lining of the uterus is healthy enough to carry a foal.
By having a BSE done before breeding the mare, your veterinarian should be able to evaluate your mare for her ability to breed, conceive and successfully carry a foal to term. There are no guarantees of success in breeding programs for horses. But, the knowledge you gain from a BSE will help you to determine whether your time, effort and money is being well spent on a particular mare.
Randy D Volkmer, DVM