How heritable is conformation?

I’m just wondering how heritable conformation is? I don’t really think I have seen any studies saying that if the mare has cow hocks, the foal has a 50% chance of having cow hocks?

I don’t think that’s how conformation works, though it might work for certain color alleles, like eye color?

I mean, cow hocks could be from different issues, not just one trait. You’d want to see other offspring to get an idea of what passes.

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Statistically the foal inherits 50 /50 from dam and sire.

Some things are just yes/no, particularly color and markings and some genetic diseases. But something like cow hocks is not a single genetic marker but a number of different genetic choices affecting the hind legs.

Realize as well that the sire and dam themselves possess a genotype that is never fully expressed in the phenotype in front of you.

I think that the reason many top sires are prepotent and seem to “stamp their get” is that they have been bred to be more homozygous in many key traits and therefore more likely to replicate their phenotype. Most mares are not as carefully bred as the top sires.

That said, I watched the online fortunes of a local Paint stallion. He had very straight post legs and he passed them on to all his foals, regardless of the mare. I’d be curious to see his own sire and dam. Maybe post legs were a huge family tradition.

Anyhow, a good rule of thumb is not to breed a mare if you won’t be happy with any of her conformation flaws replicating.

Conformation is 100 per cent hereditary, its just that 100 per cent is split between two parents.

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Ah - yes! Conformation like every other trait is highly inheritable - which is why wb breeders have inspections and why all breeds or wbs have registries. These registries allow tracking the pedigrees and finding breeding nicks that are both positive and negative. THE MARE IS THE TREASURE TO MOST BREEDERS AND EXTREMELY VALUABLE AND IMPORTANT - MORE EVEN THAN THE STALLION! The mare is thought to pass more of her attributes and other traits than the stallions. Stallions such as Contender and Landgraf are known for poorly conformed hocks/weak - but they are very well known and a proven producers - both have weak hocks and you don’t want to line breed closely here. The Holsteiner breeders have put a huge value on their broodmares for decades and only allow mares with an unbroken Holsteiner pedigree in their highest books. Understanding your mare’s conformation and pedigree are two of the important components in matching her well with a stallion to strengthen where she is weak possibly or at least not emphasize it. Some traits seem to be more heritable than others and some are more prepotent in passing them along. A really poorly conformed horse of either gender should probably not be considered a breeding candidate. Many that excel in shows are not necessarily good breeding stock.

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There have been a number of studies on warmbloods in Europe about heritability of conformation as well as the correlation to that and injuries or lameness. I am remembering a German one that said that limb angles were one of the least heritable traits but I can’t find it right now. I did find this article which has some discussion and also cites a lot of other studies and some more answers might be found there for you.

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Conformation is highly heritable. There’s a reason there are whole lines of QHs with sickle hocks, WBs with excellent pillars of support, TBs with long sloped shoulders, WBs that are tall rectangles, and more.

But no single conformation trait is determined by a single gene, so no, there’s no 50/50. Conformation is about bone length and bone angle.

Breeding a long-backed mare to a short-backed stallion is least likely to get you an average of the 2, and most likely to get closer to one parent or the other.

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I find conformation interesting. I’ve never bred and don’t intend to, but I have found with my horses that they tend to look like their grandparents, more than their actual parents. I don’t imagine this is true in all cases but it’s interesting to me.

As for the Paint stallion with post legs… I’d be curious his breeding too. If you remember the QH stallion Kid Clu… can we say fence posts? Why anybody bred for that, to that, I will never understand.

There are lots of stallions who stamp their get. Gatsby’s kids for example look soooo much alike, no matter the type of mare, because he makes them all looks much more like him.

Post-legs - highly desirable in the Halter world :face_vomiting: :rage:

I recall a study that may have been by KWPN that said lower limb heritability was around 33%, and that environmental factors had a rather large impact on how lower limbs turn out.

That said, I would not breed any horse with legs whose conformation could cause unsoundness.

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Have a look at page 30 here - a number of articles are also cited: https://ulir.ul.ie/bitstream/handle/10344/1639/2010_Morscher%2C%20S.pdf?sequence=6