It’s like asking how long is a piece of string?
I bought a 16.3hh 3yo hanoverian gelding. He looked “done” and parents were 16.3 and 17hh. Between 3 and 6yo he grew another hand, and topped out at just under 18hh!
I have a few homebreds:
-The gelding is by a 16.1 1/2 stallion out of a 15.3hh dam. He was 14.3 as a 2yo. He’s now 4yo, and still about 14.3. He’s chunked out for sure, but I don’t think he’s grown more than half an inch in the last 2 years. I was hoping he’d finish out at mom’s height, but nope, I’ve got a fancy hony I have no idea what to do with.
-The filly is sired by same 16.1 1/2 WB and dam is a big bodied 16.2. The filly had a very rough start in life, which may have impacted her final size. She was about 14.2hh as a 2yo, and now, at 4yo, she’s about 15.3 and butt high and narrow, so looks like she might get another inch or so before she’s done.
-Last one is 3/4 welsh, so a different story from my WBs above. He’s by a section B out of a 14.2 welsh x QH dam (who’s full brother finished at almost 15hh). This one was probably 13.1 as a 2yo and I hoped/expected he’d finish as a top of the line medium. He’s 3yo this year and last time I measured him he was 13.3.
So, like the snug T shirt that shrinks in the wash, while the loose fit clothing you want to shrink never does, murphy is a dick when it comes to horses. If you want them to grow bigger for your long legs, they stop growing at 3 and stay petite-bodied. If you want them to stay smaller, they keep growing till they’re 7yo and shoot up another hand and a half. Genetics are part of it. So is nutrition. But sometimes they just go their own way… one of many reasons why breeding is a crapshoot.
