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A monkey mouthed (underbite) broodmare

Has anyone bred a mare that has an underbite (monkey mouth)? Did it produce offspring with jaw malformations? (either parrot or money mouthed horses). I have a mare who is a lovely mover, sound with USEF jumping record. Thinking of breeding her but she has an underbite. I have read several articles about this. Some of the articles say it is genetic and not to breed a horse with a monkey or parrot mouth. Other articles say it’s not inheritable.
Does anyone have experience with this?

While it may not be heritable in all cases, there is the potential for it getting passed down to the foal. If it were my mare, I would not breed her.


It really would depend on the quality of the mare for me. I wouldn’t say “don’t breed ever”, but there would be some heavy thought going into this.

Some things that would weigh my decision: was the mare successfully sound and did she have a consistent show record? If so – I would rather see a show mare with an underbite bred, than a mare that has never done anything with good conformation. Is the underbite severe, would it impact ability to chew? Most underbites that I’ve seen have been minor and the molars are still able to masticate fully.

The mare’s eligibility in certain registries would play a factor also. Has she been approved anywhere?

There’s really no such thing as the mare (or stallion) with perfect conformation. Everyone is (or should be) breeding for improvement. My personal opinion is an underbite is a lot less serious of a flaw than limb or spine malformations.


My mare has had no issues with her mouth, although we do check her mouth frequently and she does need dental work more often than my other horses (instead of once a year, I probably have her teeth done every 9 months to make sure she can chew effectively. She has been shown in the jumper ring consistently up to the 1.20 meters and has a good/consistent show record. She has had one baby but I don’t know where the baby is and I’m dying to know if her colt ever had any issues. I know it is almost always better to buy them breed (things can go wrong/get expensive quick/you never know what you are going to get) but this is the nicest mare I had ever had as far as quality gaits, show record, personality, conformation and soundness. She is 16 years old this year and having little kids myself I know we are not going to be showing this year and so breeding popped into my head. Two trainers I have worked with have confirmed that she is nice enough to breed, but neither of them know about her mouth. I forget to mention it. I’ll post a confirmation shot.

I just wanted to say that if you succeed in producing a money mouthed horse, I want to buy that! The kind where money comes OUT that is, I already have 2 that have excellent talent at taking money IN. :lol:


No.I don’t know anyone who would breed a mare with a mouth deformity, but that’s just the opinion of the breeders I’ve known. No way would the mare be bred.

Breeding is risky enough with animals that have good conformation.

It’s your call. If you are keeping the foal and don’t mind if it has a mouth deformity…

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Thank you everyone who responded. Looks like the consensus here is don’t breed, which is actually a relief. Now I can relax, enjoy my mare for the next few years and keep my eye out for a baby already on the ground (sans an underbite) in the next few years.


Enjoy your mare. It’s wonderful when you have one that you really love.

She really looks nice, but I just wouldn’t breed her with that fault. I think you’ve made a wise decision. :yes:

I knew a dog owner once that was so relieved the OFA hip rads on her bitch came back as mildly dysplastic. Just bad enough she shouldn’t be bred, but not bad enough to likely ever be a problem for HER. The dog’s breeder was a co-owner and the contract stated that if she was OFA clear she would be bred to the sire of breeder’s choice or some such. The person who actually lived with the dog was thankful to get an “out” from dealing with breeding headaches!