In humans, we don’t usually castrate them because it throws their hormones out of whack, and causes all kinds of issues, but wouldn’t that also be the case for some animals, since their hormones systems are fairly similar?
Why is it that that we remove the testicles entirely, rather than giving them vasectomies like we do for humans?
At least in people, though, doing that can also cause problems like bone density loss, which seems like it might cause more health issues than it would otehrwise help.
That’s the case in doing it too early in animals as well, especially noticable in larger breeds. There’s been a longtime pushback for dogs to get spayed / neutered at later ages, than one size fits all.
Also there are other interesting studies that differ between humans and animals, such as the lifespan of animals that are neutered / spayed tends to be longer than the other way around, and supposedly in humans it’s the opposite.
I didn’t do a ton of vetting when I was researching the information though, so I don’t know how well the studies were controlled and what they accounted for.
Edit: Also some vets do offer vasectomies as an alternative to neutering, but it is usually far more expensive.
spayed/neutered humans do live longer than their intact counterparts. There was a paper on Thai men who were castrated to serve as royal guards. IIRC, they lived 17 years more than average.