For some breeders, lowering a breeding stallion’s testosterone concentrations in the off-season is, among other uses, an attractive solution for undesirable behaviors. They can do this by administering a substance that suppresses the horse’s hypothalamic-pituitary-gonadal (HPG) axis, which regulates testosterone concentrations.

Gabriel M. Davolli, DVM, MS, a theriogenology resident at Louisiana State University’s School of Veterinary Medicine, studied one gonadotropin-releasing hormone antagonist’s effects on suppressing the HPG axis and presented his results at the 2015 American Association of Equine Practitioners Convention, held Dec. 5-9 in Las Vegas. He conducted his research while completing his master’s degree at the University of Kentucky’s Gluck Equine Research Center, in Lexington.

Gonadotropin-releasing hormones (GnRH) essentially tell the stallion’s reproductive system to produce testosterone. The appropriate antagonist would block this function