Young friesian mare behavioral issues

Help! I bought a four year old a while ago. I’ve been riding her for months and she has been an angel. I have her in full training with a professional. She went to her first show and clinic last month with a score of almost a 70 %. We were going to try her in the FEI four year old class but before the qualifying show she started bucking and getting opinionated under saddle. We brushed it off as ulcers from her first show this season and treated her with a week of ulcer guard. She went to the show and acted terrible. She started rearing and tried to run back to the barn. She got very backed off the leg and refused to trot or turn when asked than threatened rearing. Now that we got back home she contributed to rear outside. Today, she was slightly better And was good but my trainer wouldn’t let me get on because he still felt Her backed off the leg . She is a four year old mare, so I wonder if it is a heat cycle? I am having her scanned for ovarian cysts and looking into hormones (although I have my qualms with regumate and would love to avoid!

what I know it’s not

  1. Being at a show - she was perfect at a show three weeks prior and got an amazing show
  2. Me being over faced. She was being ridden solely by the professional (to prep for fei four year olds) when this started happened. also she has never misbehaved when I ride her.
  3. Ulcers or leg/back lameness- she has been on ulcer guard and banimine to no success. She is extremely sound and athletic.

I worry it is medical because of her sudden change of demeanor. She went from being a sweetheart to being a little scary. She’s only 4 and it might be a phase. But has anyone had similar situations with a 4 year old friesian mare changing her personality over night? I’m very upset and miss her old personality any help is much appreciated.

Could you provide a bit more information about how/when you’ve been using the ulcer guard and banamine? When was the last time her saddle was evaluated by in person by a fitter? Any changes to turnout, grain, supplements, tack, turnout buddies, or farm dynamics?

I agree this sounds like pain. If you only did a week of ulcer guard it really is worth scoping and if necessary doing the full month treatment and rescoping. Banamine can also really upset the stomach so in theory you could have an ouchy stomach and a pain issue and while the banamine helped one it flared the other.



we started using the ulcer guard when we noticed she was backing off the leg and bucking under saddle and we continued it into the show and she’s still on it. So it’s been about two weeks now. We tried banimine for two days and than stopped it more as a test to see if it was leg pain.

she was scheduled for a saddle fitting but she was bucking so we had to reschedule for August.

She has always been turned out in a pasture with 5 other friesian mares. She’s the boss mare and has a bossy personality and is very in your face and always has been. She tries to heard from the ground. Her best friend in the pasture came to the show and she spent the entire time calling out to her (which was a new behavior). She also goes to a barn with other friesian stallions and she’s been peeing and pawing(also new behavior). Which is how I came to the mare hormone theory initially.

I think with any young horse in training where they are growing and muscles are changing, saddle fit must be checked often by a well qualified fitter. She is telling you she is uncomfortable,

this is also the time that she is losing baby caps and growing her adult teeth. Best have someone check to make sure she is not retaining a cap

I would be concerned that she is being pushed too quickly, she may need a less intense schedule

I personally would avoid Regumate as much as possible. It is not entirely a safe product to be around. People chuck it around without good, clear understanding that this is a hormone that can cause problems with humans if it is not carefully administered and the clean up done well

vet check ASAP saddler check ASAP


Check your tack. If she has developed recently, her saddle may not be fitting as well as it used to. To me this sounds like the behavior I experienced before I figured out horsie did not like the fit of my saddle.


Tack needs to be checked frequently, especially in a young developing horse.

I do think hormones and issues with the ovaries are something to consider in a mare, so I agree with you doing some investigating there.

The other thing to consider is hindgut ulcers. Ulcerguard/Omeprazole can actually irritate ulcers in the hindgut. If you feel she has gotten worse with treatment then I’d investigate there as well.

Usually something like this screams pain, and it’s important to give a horse, especially a young one, a positive training experience not associated with pain. So I’d lay back on the work while you sort this out. You can handwalk in the trails and do groundwork as these horses usually enjoy people intersection and activity.

What was her work load like? She could’ve also reached her mental capacity. She is young. I’d make sure she isn’t being drilled and gets to do things such as hacking, long reining, light pole work, etc. So she has a variety of “light” work to keep her mentally fresh. Some horses also don’t need to be worked everyday. I have one of these and quality sessions go a long way versus quantity and hours/consecutive days in the saddle.


She is FOUR! My horse was sweet as pie from 3-4.5. At 4.5 he started doing some of the things your horse is doing and he had been to shows, trail ridden etc. So don’t rule out the show etc. My horse was bratty until he was 6 and tested me constantly, tried to run out of the ring at A, wanted to go back to the stabling area, called to any horse he was next too. We worked through it, he was also very sensitive to saddle issues so I had too have it checked constantly until he was through growing.edited to add that I sent him to my FEI trainer for three weeks when he was 4 because I was not quick enough to fix the spin and buck…she would not let him come home until she was sure she had him behaving better and stopped the spin and buck.


I would check tack, teeth, and possibly a reproductive exam. If she’s getting strong heats or has some sort of cyst that would explain a lot. I would also make sure she gets plenty of trail rides and relaxing field hacks so she isn’t sour in her work.


I would look at diet, too. Has anything changed in her situation which would potentially be an issue?
my mom’s Friesian cross is allergic to alfalfa and hallucinates on it. She was only getting a small amount and changed from the horse we bought as a last horse for an older woman to a horse who was constantly reacting to visible things in front of her and freaking out. Within two days of eliminating alfalfa she was fine. This behavior happened when not being ridden as well, which told us it wasn’t riding related.


Peeing around stallions is a sign of heat. Is she winking?

If she is in heat she might be in pain…just from the heat or from an ovarian cyst.


She’s 4, wait until next year when she’s 5. Oof.

Definitely get her checked for cysts, rearing is quite extreme and a definite signal that something is not right. Regumate might be necessary to make her comfortable. If so definitely get the dosing gun, it makes the handling a non-issue once attached and just squirt it on the feed.

For what it’s worth my mare at 3 years old was an absolute angel, at 4 was good but needed the hormonal leveling that Regumate provides, at 5 this year I attempted to see if we could graduate from Regumate. 2 heat cycles this spring and she rubbed her back end completely red raw and had scalds from peeing even with cleaning her everyday. No more, back on the meds. She’s still young and figuring things out but sometimes they just need a little help to be comfortable.

If not cysts and Regumate trial is a no-go then absolutely get saddle fit checked. My mare went from a wide tree with mattes half pad to a medium tree with half pad now to just the medium tree saddle alone. Their back muscles and topline change so fast as youngsters.


I would definitely make sure her saddle and teeth are ok, then for sure look into her repro health. The fact that she’s interested in the stallions and her sudden bad behavior makes me think her uterus or ovaries are doing something that hurts. It’s hard being a baby horse sometimes.


I will second what others are saying about ovarian cysts. A mare I owned had very painful cysts that made her behavior change. Lots of bucking when she was in heat. My current mare is on Regumate. She was okay during her heat cycles as a three and four year-old, mostly very resistant. She became a real pill during her heat cycles in her five year-old year. I have a glass syringe that screws to the top of the Regumate bottle and wear gloves when administering. It goes on her feed.

Saddle fit is always important to check. It’s amazing how horses can change as they develop and put on muscle. I’m looking for saddle # 3 right now for my mare. She is six and has really changed, especially in the withers.

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Welcome to the world of young sporthorses between the ages of 4-8. Not to say that you shouldn’t look at some of the medical things being suggested, but my money is going to be that she’s 4 and has suddenly realized that life is hard. Quite often, youngsters are wonderful as 3 year olds and into their 4 year old year. Sometime as a late 4YO or 5YO, we start to ask more and they start to rebel. Some have short lived phases, and others stay nappy for a few years. I bough my mare as a delightful 5YO. It was late that year and through her next year that I just had to grit my teeth and get through every ride. It wasn’t fun. And yes, she was sound and healthy. Just opinionated and not always so much with the wanting to work.

My advice is look into her health, cysts, saddle fit, teeth, but if she’s sound and you can’t find an obvious reason for the resistance, just put your leg on and ride. It’ll pass.


Hi everyone an update is she had a huge ovary cyst that the vet said was causing her immense pain! She is now being treated and should be back to work in a week or two! Thanks for all your suggestions.


I think I might have been in the warmup at your show! if so, lovely horse and yes, she was a little scary!

Glad you found the root of the problem, fingers crossed she’ll be back to her usual self soon.

I’m so glad you figured out the issue. And for what it’s worth, yes they all go through bratty phases but I generally find with mine (bought at 4, just turned 6) that normally never bucks, if he starts bucking (usually just canter depart) and gets really backed off, it’s a sign he’s due for a saddle flocking adjustment. Good for you for listening to your mare.