Horses castrated in their weanling year do not develop some of the musculature and neck and facial features associated with stallions. These early geldings keep finer features, thinner necks and lighter muscle mass, though they can grow taller than they might if left entire. Many castrations are performed on colts between one and two years old, and due to the larger size of the testicles, the incisions must remain open. Since open incisions are more susceptible to fly irritation, spring and fall are the preferred times of the year, before or after fly season. Veterinarians use two castration techniques.
Additional anesthetic is injected into the nerves of the testicular cords.
The surgeon stands near the horse, leans over and removes the testicle using a special piece of equipment that cuts the cord, crimps and seals the blood vessel and removes the testicle. The veterinarian usually ties up one of the horse's hind legs and performs the surgery while kneeling over the prone animal. Each approach has its advantages and disadvantages and owners should discuss the choices with their veterinarian. Neither technique is universally better than the other. A new technique using a clamp-like devise applied to the testicular cord is being tested at the University of Georgia Veterinary School.