Ready Mares in Fall for Foals in Spring

Nov 29, 2016 / General Care / Preventive Health / Horses

[mares- Dr. Igor Canisso]

Reproductive Health, Vaccinations, Nutrition Are Key

While some may consider it a bit premature to be thinking about spring, if you are a horse owner expecting a foal out of your mare or hoping to get your mare in foal, this is the perfect time to start planning.

Dr. Igor Canisso, an equine theriogenologist at the University of Illinois College of Veterinary Medicine (who is ultrasounding a mare in the photo above), provided some helpful tips for the diligent mare owner looking to jumpstart the breeding season. He broke down the preparation into three basic steps: fall workup, nutrition planning, and lighting management.

Basic Reproductive Health

The fall workup is something you should discuss with your primary veterinarian.

“This is the most critical time to evaluate any pregnant mares for signs of placentitis, one of the leading causes of pregnancy loss,” says Dr. Canisso. She should be monitored for premature bagging up, vulvar discharge, and “sucking air” through the vulva.

Air sucking indicates that the integrity of the seal formed by the vulva or internal parts of the vagina have been compromised. If this issue arises in your mare, your veterinarian may elect to perform a Caslick’s procedure or expand an existing one. This simple procedure involves suturing part of the vulva together to lessen the risk of fecal and urine contamination and to reduce air sucking.

A fall workup is equally important to a mare that is about to be bred.

“We want to make sure she is clean, that there is no infection in her uterus, and that she doesn’t need any reproductive procedures. If she does, take care of those sooner rather than later. We want her to have been clean for a while by the time the spring breeding season occurs,” Dr. Canisso recommends.

Vaccinations and Deworming

Both pregnant and non-pregnant mares need to be up to date on vaccinations.

Also, additional vaccinations are recommended for pregnant mares, like the vaccine for rhinopheumonitis (equine herpesvirus) that can cause abortions. Mares will need vaccinations for this at five, seven, and nine months of gestation.

You and your primary veterinarian should address not only vaccinations but deworming. Many horse owners practice deworming regardless of their horses’ worm infection status. It is best practice to ask your veterinarian to do a fecal egg count to see if your horse needs deworming. Both pregnant mares and mares that are going to be bred can suffer issues that can impede their reproductive systems if they have an overload of parasites.

Eating for Two

Once you and your veterinarian get your mare’s reproductive health up to par and her vaccinations up to date, you should also consider evaluating her nutrition plan. Fall is the best time to alter an animal’s body condition (weight and its distribution).

In non-pregnant mares, you want to make sure that they are at an average, healthy weight. A mare with a low body condition score may have trouble getting pregnant, while one that is too heavy may have difficulties carrying and delivering the foal.

Dr. Canisso recommends sunflower oil as an additive to increase a mare’s weight.

“Sunflower oil increases energy density of the diet but won’t cause gut overload with carbohydrates if given at moderate amounts. Owners should be careful with feeding grain. High amounts of soluble carbohydrates can lead to laminitis,” he says.

If you find that your mare is having trouble gaining weight despite your best efforts, you should discuss with your veterinarian whether to evaluate her for metabolic issues or if she is experiencing chewing problems, so check to see if her teeth need to be floated. Both of these issues make it very hard to maintain a good body condition score, and both are most easily remedied in the fall.

Keep the Lights On

Finally, artificial lighting management is very important this time of year. The shorter days in late fall and winter alter a horse’s metabolic and reproductive hormones, which is what induces winter anestrus. Anestrus is a time during winter when mares do not have reproductive cycles (ovulatory heat) and thus cannot get pregnant. Artificial lighting will cause mares to come into heat earlier in the season or sooner after foaling by simulating a longer day.

Some mares that foal early may go through a winter anestrus after foaling. However, mares well-fed and kept under lights are less likely to have this happen.

“Mares should be put under lights by the first of December. The easiest way to add light is six hours at the end of the day. This is a good time to bring mares into the barn to be fed, so you can evaluate their eating habits and also keep them protected from winter weather and under lights,” Dr. Canisso recommends.

If you have any questions about preparing your mare for the spring breeding season, contact your local equine veterinarian or staff from our Veterinary Teaching Hospital.

By Hannah Beers

Photo by L. Brian Stauffer