My 17 yo maiden pony mare was ultrasounded as NOT PREGGO last spring when she actually was in foal. Since we believed the vet we kept her in work, just finding out this past Thursday she is a month out from her due date of May 25th (AI’d last June 25th). Foal very healthy, even kicked the vet during palpation ! Mare actually just had a GREAT jump school on Saturday ! We have competed her several times in this condition and I have to say her little leasee has also been riding the beejeebus out of her thinking she was just fat and needed conditioning ! I will be bringing her home this wknd for some R+R bf baby but I am concerned about the effect the work has had on her and foal, the fact she has missed all her foal nutrition, etc. How long has anyone else worked a mare into her pregnancy ? Anything else I should be concerned about ? I am hoping staying this fit will actually make the delivery easier on her ???
May I tell you a little story.
Years ago a pony mare was bred. Very well known breeder had her checked not in foal.
Pony was sent to another trainer after being checked 3 times not in foal. Pony was said to be a bit “bright”. New trainer put her into their program and said she was just a “kick and go” pony. Pony kept showing. Lovely and quiet.
She showed at the show on Sat. and Sunday early am, the braider came in to braid
and their was a foal.
Resulting foal, BLUE ROCK , went on to become a very very good show pony for a number of years.
Just sayin…she will be fine.:lol:
Bought a 20 something year old Irish TB from a breeder as a school mare. Breeder said she was barren and had been for 5/6 years and used her as her stallions companion. Her record of produce also confirmed with the sellers statement last foal 5 years old.
Brought mare home used for a few months and noticed she was getting VERY round and her belly had a suspicious keel shape to it. Had her checked just for the hell of it and ooops vet said their was a very large near term foal in there.
He said let her keep working just step her down to light W/T for another month then give her off. Since she was older he said keeping her in condition would help make foaling easier on her/less taxing.
3weeks later brought mare in for the night she was dripping milk and foaled a very large colt.
Both were just fine.
I bought a little mare for a resale project from a vet friend. Bought her in May, about January I just couldn’t understand why she seemed a bit fat even though I kept upping her workload and cutting back on her feed. I took her to my trainers for a regular lesson and I noticed her “fat” was a bit more on one side than the other. Took her to vet the next day, yep, baby in there. Asked vet I got her from and he said no way, she wasn’t exposed to any of his stallions. I told him I had her checked and there is a very large foal (as in far along) in there. Then he says well, one stallion did get in that pen for a couple days but he couldn’t remember when. Needless to say she foaled about a month later and all was fine. My attempts to skinny up mom didn’t seem to have any effect on the foal thankfully.
I had an Arabian mare once that was declared not to be in foal. I started getting her in shape over the winter for a fifty mile endurance race in the spring and kept wondering why the mare was looking so fat. I had her checked again and sure enough, she was in foal. A month later she foaled a healthy colt.
I rode a mare that a friend bought quite hard and was jumping her regularly up to 3’6" and she was also used in the odd lesson. We found out about a month before she foaled when I was brushing her and my hand got kicked…she always was an easy keeper too…the mare was ridden regularly until she foal mostly w/t after we found out. :winkgrin: …They asked the previous owners about it and they said their stallion did get out once but they didn’t think he did anything…
Another friend had her mare turned out with a 7 month old colt (I believe he was) and they thought he was too you to do anything. Basically after a summer at grass she came home, was ridden regularly. And the same thing happened as above…the owner wasn’t impressed as she had planned to show that coming summer. 
My mare loves to be in work, when I didn’t have 2 young kids I rode her everyday. When I was expecting my daughter and stopped riding/showing my friend rode my mare 7 days a week for me and she happily came to the gate for work everyday. She was 6 months in foal when this video (Part way down the page) was taken. :lol:
I think 5 months should be the cut off because at 6 months the foal doubles in size and then increases at close to that rate after that. If the mare is in work and fit those muscles that need to start letting go to accomodate the growing foal are staying tight. We feel this is an important time for the mare to allow the foal to grow, develope and have room to accomodate that growth in a correct manner. Hope this helps.
I would really like a vets take on this as I have wondered about this as long as I have been breeding. And since i have been prego myself I have differing opinions - I rode for a long time into my preganancy - stayed off the stallions and just rode the easier horses to reduce the chance of getting injured. My mother rode well into being preg with my sister…no ill effects. I continued running until 3 or 4 weeks before I had Carter - but when it comes to my mares I seem to be much more protective. 2 of my mares are VERY clear about when they no longer want to be ridden and that is about 6 months but i also know competition mares in Europe that they ride in competition for quite a while and they go back to work a month later and they have the belief that these mares when kept in better shape have an easier time foaling… just my thoughts.
We rode our mare up until the 8th month.
I bought a 9 month old filly off some one that rode the dam up until the end of the 10th month as they did not realize the mare was in foal…had been checked but was missed.
My vet told me of mare that was at a show and when they got home they unloaded the mare as soon as she got off the trailer she went down and proceeded to have a foal.
Dalemma
I wouldn’t say it’s a good idea to keep riding up until the end, but…
Many years ago my instructor leased a mare (ironically named “Mama”) as a lesson horse. She was a fugly, fat thing, but very sweet. Foxhunting was part of the deal at this barn… one morning everyone was getting ready to go to a hunt, and Mama’s rider noticed that she was uncomfortable and had a full udder with milk droplets on the teats! And I am sure you can guess the result… one fugly, sweet little colt born the next day. Mama’s last foxhunt was 2 weeks before the colt was born, and she’d done lessons up to two days before.
It was only after the fact that the guy my instructor got the mare from confessed that he’d turned out his fancy stallion with the mares for a few months. He gave Mama and her colt to my instructor. Fancy stallion did nothing to improve on Mama, sadly… My instructor kept the colt and had him gelded and I am sure he became a nice lesson horse just like his dam.
mine told me to take a hike at about 7 months
And a friend had the story of a race mare in training that was too fat and kept getting slower and slower. They kept cutting her feed and working her harder. After her last race they found a foal in the stall. She was fine.
The mare will tell you. My mare likes to work. Last time around (her fifth) I showed her 3rd level at 7 months, backed off at 8, worked a bit at 9, and was just toodling around at 10. The belly tends to get in the way of the canter at 7/8 months.
I think in general keeping them in shape is a good thing. I got back on her two weeks after and she loved the work. It’s just the milk bag made her a little bowlegged.
