Preparing your Mare for Breeding Season

A body condition score of 5 is deal for a broodmare going into the breeding season. (Graphic courtesy of the Kentucky Equine Research Institute)

By Lauren Lamb, DVM

With breeding season upon us, it is time to start preparing your brood mare for the breeding season. Your brood mare may seem perfectly healthy, but having a breed soundness exam performed prior to having your mare bred may save you time and money.

A breeding soundness exam can reveal abnormalities within the reproductive tract that can be corrected prior to breeding your mare.

Correcting these abnormalities prior to breeding your mare will increase the chance of your mare being foal. A breeding soundness exam can be performed on the farm if proper equipment is available for physical restraint.

The breeding soundness exam starts with an overall physical exam of the brood mare. Just because we are trying to get the mare in foal does not mean that we can forget about her overall health. Entering the breeding season, a mare should have a body score of five on a one to nine scale. Having a mare below a score of five can significantly decrease the chance of you mare getting in foal.

Having an obese mare, body condition score of nine, will also significantly decrease the chance that your mare will be in foal. Blood work, such as a complete blood cell count, serum chemistry or a serum amyloid A test, may be warranted if your brood mare is significantly underweight despite being fed a proper diet and having a good appetite.

The next step in a breeding soundness exam is a visual inspection of the mare’s external genitals. The external genitalia include the vulva, anal sphincter and perineum. The vulva should be perpendicular to the ground and make an air tight seal. If the vulvar lips do not make an air tight seal or the top of the vulva is tilted forward, the mare will be predisposed to developing an infection in the vagina and/or uterus.

This infection is caused by air being sucked into the vagina or uterus or urine pooling in the vagina or uterus.

A Caslick’s suture is a simple surgical procedure that can be performed on a brood mare with poor confirmation of her external genitalia. A Caslick’s suture is done with the mare standing and sedated. The vulvar lips are blocked with lidocaine and the top 2/3 of the vulvar lips are suture close. This procedure is done after the mare is confirmed in foal. The suture will need to be removed before the mare foals 11 months after being bred.

After visual inspection of the external genitalia, the breeding soundness exam will proceed to the cervix, uterus and ovaries. These organs are located in the mare’s pelvic canal and abdomen. The cervix, uterus and ovaries are examined via rectal palpation and transrectal ultrasound.

The ovaries, in late fall and winter, will be small and inactive. The ovaries become more active during the spring and summer months. We can artificially speed up the ovarian activity in the late winter months and early spring months by putting mares under light for 18 hours per day.

If you can easily read a newspaper in all areas of a mare’s stall, the mare is receiving enough light to activate her ovaries and jump start her estrus (heat) cycles.

Pick up the February issue to learn more!