I know geldings tend to be taller than stallions, but how does that happen? Do geldings grow for a longer time period? Or to they have more intense growth spurts? Will a stallions joints close earlier?
It does.
Sex hormones are a factor in the closure of the growth plates in mammal species. Even in people, its been observed that delayed onset of puberty is tied to longer growth period of the long bones. In dogs, early spay/neuter also results in taller dogs. Giant dog breeds now get the recommendation to not neuter until the 2 year mark so that the legs can finish growing appropriately all the way up to the hips and shoulders
In horses, this is why stallions are usually a bit shorter but build muscle more easily. Testosterone triggers a speedier closure of the growth plates and a shift of priority to muscle.
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That’s what I thought. Now I need to dig up some reference material and win an argument on Facebook! 🤣
A Texas college did a study years ago, using many closely related western horses. The geldings grew taller than the ungelded colts on the same diet and exercise program, even full brothers. Western Horseman Magazine is probably where I read about the study. They might be able to reference the article if you contact them by email or a phone call.
We purposely geld our colts after they reach their first birthday. This is to keep them “smaller” than 17+ --18H, which is too big for our uses. They are genetically bred to be large, but gelding young makes them huge. Growth plates in legs close sooner because they have testosterone in their bodies as stallion colts, not geldings. They do continue growing, finishing up around age 6yrs.
Ours are kept in the gelding group, older geldings keep their high spirits kind of squelched with herd disipline. This teaches colts they are LOW in herd hierarchy, they don’t treat humans as toys! Not being heavily grained for growth, ours don’t seem too interested in our mares, a couple fences away. They have no physical contact with mares, not interested in breeding, so they have all been easy to handle, stay in their pastures. Without much grain fed, all the hay or grazing they will eat, the reach their genetically determined height, just slower to do that. We feel slower growth builds a stronger boned, sound horse to use over the next 20+ years.
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Agree with the above: gelding results in taller animals. Testosterone is related to the closure of the growth plates, so the earlier the gelding program (before onset of hormones, so to speak) the longer the plates remain open.
I don’t know about horses, but - fun fact- the castrati (boys castrated before puberty so their singing voices remained soprano as adults) were far taller than average.
I wonder about the effects on long term soundness. I’ve gelded anywhere between 6 and 15 months.
In my reading the Internet this last couple of days I keep coming across recommendations to not neuter large breed dogs until they’re 2yo because the more rapid growth can cause joint problems. I’m not sure this can be extrapolated to horses, but I thought it was interesting.
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