At what age do horses stop growing?

At what age do horses stop growing? Particularly thoroughbreds? CoCo is already 17hh and her previous owner said there is a possibility she has some growing yet. Her sire was 15.3 and I'm not sure how tall her dam was.

Thanks!

already trying to figure out how my short self is going to get on.

In my experience TBs finish up around 3-4 years old. Warmbloods go a little longer to 5-6 years. It totally depends on the individual horse though, it's a tough call.

How old is she?

She's 4, rising 5. So I'm hoping she's done all her growing and just has to fill out.

All horses, no matter what age, are completely solid and finished growing when they are six in terms of bones, ligaments, joints sealing etc. Some may finish growing their height at an earlier age, but no matter what breed they are not completely finished until six. Obviously you can change the amount of muscles and amount of fat no matter what age with proper feeding and exercise.

Dr. Deb Bennet has a wonderful article on this.

http://www.equinestudies.org/ranger_..._2008_pdf1.pdf

On page 8 of the article you will see where she says, "These do not finally fuse until the horse is atleast 5 1/2 years old (and this figure applies to s small-sized, scrubby, range-raised mare. The taller your horse and the longer its neck, the later the last fusion will occur. And for a male add six months. So for example, a 17 hand TB, SB or WB may not be fully mature until his 8th year."

So I would not be surprised if your mare grew a bit more. It may not be much, but she is still maturing if she is that tall. Also, muscling out will also increase the height of the horse by a bit above and beyond just the skeletal structure.

Yipes.

Thanks for that article Cat!

Sorry to hi-jack, but what is everyone's experiences with QH's? When do they stop growing height wise?

I would read Deb Bennett's article. It's hard to predict what height they'll be when they stop growing, it's like predicting how tall your kids will be and when!