Question: We recently purchased a 10 year old Standardbred stallion from a local breeding farm. He retired from the track 4 years ago and since has been used only as a teaser stallion and supposedly had never actually been used for breeding. We bought him hoping to use him as a driving horse. He was gelded two months ago, but still displays very stallion like behavior. We cannot let him out with mares or other geldings. He herds the mares around and will mount if given the opportunity. He cannot even be stalled right next to a gelding. He kicks the stall wall, keeps his ears pinned, and paces around in his stall. Will his aggressiveness toward the other horses go away? Thanks for any help.

Answer: Gelding a stallion normally makes him easier to manage because his testosterone level drops dramatically. However, there are numerous reasons that could explain why your gelding is still exhibiting stallion-like behavior. You could ask your vet to perform a blood testosterone check to make sure he isn’t proud cut (bits of testicular tissue are left and the horse is still producing significant amounts of testosterone). It could take as long as six months for his levels to drop to those normal for a gelding. However, this horse has been used in a teaser stallion capacity for four years, and his behavior may have nothing to do with his testosterone levels. While he may never have been used for breeding, he may be retaining behaviors he’s learned while a stallion. May older stallions that are gelded will continue to display some stallion-like behaviors. You new gelding may have to be isolated from the rest of the herd for awhile and may need some behavior modification training if he’s acting out while you handle him.

It sounds as though your problem is very similar to one submitted to the University of Pennsylvania’s equine behavior specialists. Check out their article Problem Behaviors in Pastures.