A horse’s testes are typically removed (gelded) to make the animal more docile (particularly in the presence of mares), and to render the animal sterile. It is commonly felt that the short term pain experienced by the animal is overshadowed by the long-term benefits, which include greater safety for handlers.
Development of the testes
Although the testes develop near to the kidneys, during the last month of gestation they move into the scrotum. Typically, little scrotal growth occurs in the first 12-months following the birth of the foal, instead most growth occurs over the second summer, autumn, and primarily winter; by spring in the year the horse falls two the testes are almost fully grown. By the age of three the testes should be fully developed.
Prior to ejaculation, mature sperm are stored in the epididymis. At ejaculation the sperm travels from the epididymis, and into the vas deferens. The vas deferens forms part of the spermatic cord, which is cut when a horse is castrated (or “gelded”).
When is a horse gelded?
Although castration can be carried out at any age, it is often undertaken between one and four years of age. Early castration is typically avoided owing to troubles arising from the size of the testicles, as well as the animals not being desirably familiar with handling.
According to Hayes, M.H (1995), it is customary to carry out castration in “the spring or autumn” so as to avoid flies, and therefore the risk of infection.
The timing of castration can have a great effect on the outcome of the procedure; the later a horse is castrated, the greater influence testosterone has on their physical development and temperament.
How is a horse gelded?
There are several methods of castration, however, a common method is by emasculator. Castration by emasculator is determined to be much more humane than older methods utilising clamps, torsion, ligation, and cautery.
Hayes, M.H (1995) discuss’ how “most castrations are performed open” – meaning the wound is left open through the scrotum. Castration should take place under anesthesia or analgesia, with the animal either standing or recumbent.