Testicle size in stallion

[iowa]

I have a friend (really) whose four year old stallion has one very small testicle and the other one is not as large as most stallions. The vet thought that he may have been stepped on when a foal thus retarding the growth of the one. Have you found that testicle size has any influence on fertility. Thanks!

 

[Nathan Luszcz]

Yes, testicular size does affect fertility. The size (volume) of the testicles directly affects the number of sperm that an animal can produce (people included). There is a formula for horses, which I do not recall off the top of my head. So a horse with larger testicles will produce more sperm.

That said, just because your stud's are small, doesn't mean he's infertile. Just that he can't produce as many cells as a larger testicled horse.

 

[Maxi'sMinis]

Question: Do you think it is genetic and inheritable to any offspring? Is it recommended not to breed a horse that has a small testicle? I have a 2 year old that was a late developer and the late one is smaller.

 

[wpsellwood]

So Nathan what you are saying is, Size does matter

, Im sorry couldnt help. Its good information to know.

 

[anyssapark]

In my experience, a young stud, that hasnt been used much, or at all, will not have the same size testicles as a more mature stud who is breeding more mares, or more regularly. I have seen a few go from one small, or both small, to two even, good size testes in one breeding season, once they have been used.

While the size does affect the sperm production, it only takes one to get a pregnancy!!