Q. I have a male burro that was gelded about two years ago, when he was approximately 7 months old. He has always been housed in the same corral with two horses (mares) and one jenny (his mother).

Sometimes, the male burro will actively mount the jenny. For example, today I had to go outside and break the two of them up because the male burro was mounting/mating with the jenny. He will not try to mount the two horses, just the jenny. This has happened off and on since before he was gelded.

Is it normal to have a gelding burro, not just mount, but actually try to mate with a jenny? Should I do anything to try to prevent this? Is it possible that he can make the jenny pregnant (not be fully gelded)?

Heather Shatz, via email

A. Castration, which usually reduces male sex drive, does not always eliminate all male-type sexual behavior in both horses and burros/donkeys. In fact, some geldings retain fairly high levels of male sexual interest and response, even when veterinarians confirm that both testicles were removed and there is no evidence of elevated male hormones. In horses, as many as one third of completely castrated geldings will still achieve full erection, mount, insert, thrust, and ejaculate, especially when given pasture free access to females in estrus. In some cultures the belief is that donkey and burro geldings are even more likely than horse geldings to retain significant sexual behavior. I don’t know of any data confirming this.

Donkeys’ sexual behavior differs quite a bit from that of horses. This would certainly be part of th