theoretical breeding question re: height in pedigrees

[SnicklefritzG]

I have a coming 3 year old filly who is 14:1 1/2 and who has a full sibling who is 15:3 as a 6 year old. Most of the offspring out of her dam or by her sire end up in the 15:3 to 16:1 range.

It remains to be seen what my filly will top out at, but even if she doesn’t grow past 14:2 that’s fine since I’m short.

That got me to thinking, how is a horse’s height influenced by pedigree? Although I’m not planning to breed the 3 year old, her size made me wonder what happens when a smaller horse is bred to a stallion who tends to produce horses of average height. Would the offsprings’ height be influenced more by the smaller dam they were out of? Or is there still a reasonable probability that height could come from further back in the pedigree?

[NancyM]

I’ve had full siblings who were nearly two hands different in height at maturity.

[Edre]

There are some warmblood stallions that seem reasonably sized themselves but that have a reputation for throwing height. Current speculation I have seen is that for at least one I am thinking of, it does come from further back in the pedigree. I believe Estobar is one of these stallions.

It is interesting to think about the heritability of such things… some horses really seem to “stamp” type (overall, or certain components of their offspring) and I have never understood how that works. Some mares seem to never have large offspring. Others despite being of modest size themselves, regardless of what they are bred to seem to produce large. It’s very interesting to see but can make creating an aggregate for “rules of height estimation” to be an absolute pain!

[Piaffe11]

My coming 4 year old is currently a hair under 18hh at the moment - and that’s her butt as her withers are 3" shorter than that :eek: Her dam was 17.1 and her sire only 16hh, so safe to say I was not expecting her to be that big when I bought her as a 2 year old. Her dam had finished growing when she was broke as a 3 year old. I was hoping the same for my mare.

When I realized she is going to be a giant, I inquired and was told her grand-dam was 17.3+ (out of a 15.3 mare), which explains where the extra height is coming from. So based on my experience, the height can come from farther back in the family tree.