Ask the Vet: Preparing for Breeding Season

Question: How often should a stallion’s sheath be cleaned during the breeding season?

Answer: Cleaning a stallion’s sheath during breeding season is an important part of proper management. The horse should be teased so that he achieves an erection, and washed with warm water. Do not use soaps or disinfectants. If the stallion typically takes several minutes between washing and mounting, then drying the penis is not necessary. If he usually mounts immediately after washing, then blotting the penis with a clean paper towel will be sufficient to remove water that could negatively affect semen quality.

If it is safe to do so, a stallion should be cleaned prior to each breeding, whether it be natural service or semen collection. If the stallion is bred multiple times per day, cleaning him before the first “jump” is usually sufficient for that day. If he is used for live cover, he should also be rinsed off after mating, to reduce the chances of transmitting infection. There is usually no need to clean the stallion’s genitals between breeding episodes, even if he does not breed frequently. Frequent washing (even using only warm water), removes the normal micro-organisms that reside on the sheath and penis, which predisposes him to an infection from more potent bacteria. A study has shown that breeding stallions actually have more bacteria on their reproductive parts at the end of the breeding season, most likely due to repeatedly removing the normal flora.

In summary, a stallion should only be washed when necessary for hygienic natural cover or collection of semen. A normal amount of smegma and bacteria are part of healthy external genitalia. Dr. Kerry Beckman, Prospect, KY

Questions: There are so many things we are supposed to do to our mares 30 days prior to foaling (i.e., vaccines, deworming, etc.). What exactly is 30 days prior considering gestation is 320 to 365 days, since so many horse owners go by all sorts of calendars predicting foaling anywhere from 327 days to 343 days?

Answer: The last trimester of a mare’s gestation is an important period for the final maturation of the fetus. In addition, the mare’s body is busy preparing for a successful delivery and lactation. It is generally recommended to schedule the mare’s routine vaccinations during the period that falls 4-6 weeks prior to the due date. The normal gestational length of the mare can vary quite a bit, but the average length is 340 days from ovulation. Knowing the prior reproductive history of an individual mare can be helpful; mares tend to have similar gestational lengths from one year to the next. If the history is unknown or if the mare is a maiden, then plan to administer her pre-foaling vaccines six weeks prior to the due date. This will give her adequate time to mount an immune response and have good levels of antibodies in her colostrum that will be protective for the newborn foal.

Courtesy of AAEP