Some horse owners continue to ride and compete with a mare after she's bred, but is this good or bad for the mare and unborn foal?
Breeding mares then riding them or competing them is often a practical option with a young mare in training, and it is done occasionally with mares already showing, combining a show career with being a broodmare.
There are several possible advantages: the in-foal mare does not have heat cycles during competition, meaning she might be better focused on the task at hand. And raising a foal or two while she's young can be a plus if she becomes an outstanding performer and you want offspring to continue her bloodline. Some people like to get two or three foals from a mare to see what she'll produce instead of waiting until she the end of her show career.
Here are some anatomy and physiology facts about pregnant mares, and comments from industry professionals to help you decide if riding your pregnant mare is appropriate for your situation.
Andrea Guzinski, owner of Cedar Hill Farm in North Carolina, rides hunters, and she often continues to compete on pregnant mares. "In my program, if they are promising and I want to breed them, I breed them at 3 years of age," she said. "At that stage of their training they are not doing heavy work. After they’re bred, I continue working them as I would any 3-year-old, riding three or four times a week as they are learning to jump. They are doing small jumps and going to a lot of small horse shows, getting used to being off the farm. I'm not really showing them so much as just exposing them to all the things they’ll experience at a show."
Guzinaki generally raises two foals from a mare by the time she's 6 while just showing the mare lightly. By that time the mare is physically and mentally mature and more ready for serious competition.
"This program works nicely for me because a young mare gets to start her show career while raising a few foals," she explains.
Tia Nelson, DVM, a farrier and veterinarian in Montana, said exercise--even strenuous exercise--is usually not harmful to a mare during the first part of pregnancy. In fact, she said it’s better for the mare to have regular exercise than to stand around and become too fat.
"I feel confident campaigning a mare up until about eight months of pregnancy; it's after that time the fetus is doing most of its growing," said Nelson. She feels a mare that is kept fit will have an easier time delivering her foal.
Suzan Phillips, a breeder/trainer near Helena, Mont., has shown a lot of pregnant mares and said the main focus is to make sure they stay in condition. "You don't want to start them out in strenuous work after they are pregnant," she stated. "But if you keep them fit, they do fine. Usually my mares are already in training when they are bred, and I just continue on with them.
"A mare being ridden is in better shape to foal," she added. "It's like a pregnant woman; if you are always exercising, there’s no reason to stop just because you are pregnant. A mare should be able to keep doing whatever she's been doing."
It's wise to not push a mare too hard for the first two months of her pregnancies. Early pregnancy loss due to stress can occur.
There are caveats to riding a pregnant mare: Don't ride a mare to the point she gets overheated. Too much exertion in hot weather can be a hazard for any horse, especially if humidity is high. If a mare is worked to the point of exhaustion or gets into metabolic problems due to dehydration, this could threaten the fetus.
"Other situations that might put the mare at risk include exerting in extremely smoky conditions, like we have right now in Montana (due to wildfires),” said Nelson "This can be a risk for any horse, pregnant or not."
Transportation can be another stress. Robertshaw said he prefers not shipping a mare around the country during her first two months of gestation. "Once she's well along in pregnancy, it's not so risky," he said. "It depends on the mare. If getting into the trailer is something she's at ease with, this is not as much stress as for the mare that’s nervous about traveling."
Vaccinations are important. Nelson wants mares to have all necessary vaccinations before they become pregnant to protect against diseases that might threaten pregnancy as well as to have immunity high when traveling to shows and events.
Elizabeth Callahan, DVM, a Maryland breeder who trains and shows event horses, said you need to limit contact with other horses when taking your mare to shows. If you bring her home and she’s been exposed to rhino or equine viral arteritis (EVA), and she’s then turned out with other pregnant mares, you might end up with several abortions.
"If you can show from your trailer (rather than putting the mare in a stall next to other horses at a show) and not share water buckets, this is safest," said Callahan.
Even if your horse can't touch another horse through the stall wall, you don't know the health status of the horse in the stall just prior to your mare being there. "Take extra precautions. Don’t use someone else's towel to wipe her face, or let her sniff another horse, or share equipment," she said.
How Long Can I Ride?
Many people consider it safe to ride a mare during the first six to eight months of pregnancy, but it's wise to taper off after that. Guzinksi usually stops riding her mares two to three months before foaling. The foal does most of its growing in the last trimester. During that time the mare's abdomen will be growing larger, and if her belly becomes more pendulous, this might interfere with her balance and coordination when doing speed work. At that point she will be less agile, which could be dangerous if she slips.
"Her body is changing so quickly that her central nervous system might not have adapted yet to the changes taking place," said Nelson. "When I was pregnant and shoeing horses (the farrier part of her occupation), it didn’t matter much during early pregnancy, but in the last trimester it seemed like every day I was gaining weight and my body and brain hadn't adjusted. I was more clumsy. So I quit shoeing during the latter part of both my pregnancies. It's the same for a mare; she’ll have issues with balance and agility in late pregnancy."
How much exercise, or how long to keep riding her, depends on what kind of competition you're doing. Use common sense in what you ask a mare to do, and be aware that her body is changing rapidly in the last trimester. There's nothing wrong with keeping a mare fit all during pregnancy, but hard work that’s very jolting should be tapered off during the last half, advises Nelson.
Phillips breeds her mares in mid-March, starts riding them in April, and rides through October. Her show season starts in April/May and goes through October, then the mares are out on pasture. "I never really quit exercising them. Even when I’m not riding they are longed or have some other exercise during winter," said Phillips. Because of that, she said it’s not hard to get them back in shape after they are bred, and riding them through show season coincides with the first six months of pregnancy.
Mares doing fast work or jumping might have problems if you continue to compete in the last portion of gestation. Robershaw points out that during the last trimester, the weight of the fetus might cause a uterine torsion if the mare is carrying it low and she’s doing active work, such as jumping. A twist in the cervix and connective support structures might occur if the heavy uterus flips over.
Callahan said some mares, especially maiden mares, don't develop much belly and could probably be ridden up until they day they foal and you'd hardly know they are pregnant.
"If a mare has had a foal or two already, however, she's probably going to show her pregnancy quicker," she said.
"The mare may get to the point at six months that saddle fit is an issue; the girth sits too far forward and the saddle may slip forward onto the withers. Some mares become ungainly, with a change in gait (waddling), and are more awkward when jumping. By six or seven months, you should probably not be jumping a mare, and getting your saddle to fit properly may limit some other competitions. Mares can be safely ridden up until they deliver, as long as the rider is careful, but the size of the mare’s abdomen may limit your choices."
The fetus in mares grows very slowly in early and mid-gestation, then the fetus can a pound or more per day in the last trimester. Fit, young mares might be able to compete strenuously for several months of their gestation period, but you and your veterinarian should monitor the mare closely to ensure her health and the health of the unborn foal.
About the Author
Heather Smith Thomas ranches with her husband near Salmon, Idaho, raising cattle and a few horses. She has a B.A. in English and history from University of Puget Sound (1966). She has raised and trained horses for 50 years, and has been writing freelance articles and books nearly that long, publishing 20 books and more than 9,000 articles for horse and livestock publications. Some of her books include Understanding Equine Hoof Care, The Horse Conformation Handbook, Care and Management of Horses, Storey's Guide to Raising Horses and Storey's Guide to Training Horses. Besides having her own blog, www.heathersmiththomas.blogspot.com, she writes a biweekly blog at http://insidestorey.blogspot.com that comes out on Tuesdays.