Two doses of an “anti-GnRH injection” led to full—but reversible—sterility in a group of study horses in France. | Photo: Anne M. Eberhardt/The Horse

Your stallion has all the attributes of a successful sire, and you want him to have a performance record to back up his good conformation and bloodlines. But competing a stallion isn’t for everyone—the many special considerations that come with it run the gamut from stabling arrangements to trailering provisions. Wouldn’t it be great to turn him into a gelding while he’s competing before turning him back into a stallion again?

Thanks to immunocastration via a simple vaccine, this temporary sterilization technique has become a reality. Two doses of an “anti-GnRH injection” led to full—but reversible—sterility in a group of study horses in France.

“Immunocastration is an interesting alternative to surgical castration, but it engages the responsibility of the treating veterinarian and presents variability in efficacy and duration among individuals,” said Jean-François Bruyas, PhD, DVM, a professor at the National Veterinary School in Nantes, France. Bruyas presented his work during the 2017 French Equine Research Day