Equine Laparoscopic Castration's Success Rates Studied

Researchers and veterinarians constantly seek safer ways to perform common surgical procedures, and the castration of stallions is no exception. In the 1990s, laparoscopic castration, which cuts off the testes' blood supply but leaves them in place, was developed as an alternative to conventional castration methods that removes the testes from the body. The method soon became surgeons' preferred castration method for cryptorchids (stallions with undescended testes). But is it as effective as other castration procedures for normal stallions?

Researchers from the National College of Veterinary Medicine, in France, set out to answer this question and found that, although the procedure reduces the risk of post-castration problems such as edema (fluid swelling) and infection and allows for a shorter recovery time, testosterone production and stallionlike behavior persist in some horses following surgery.

“The procedure may lead to remnants of active testicular tissue in 12% of cases, according our results,” reported Claire de Fourmestraux, DVM, resident veterinarian of surgery and orthopedics at the college's veterinary hospital.

In their retrospective study, de Fourmestraux and colleagues evaluated data from 32 normal stallions, aged 2 to 10 years, that underwent laparoscopic castration at the college's veterinary hospital from July 2006 to October 2012. Each horse underwent endocrine tests at least three weeks after the procedure to determine if it was successful.

The team determined that after castration, 28 of the horses had testosterone concentrations below 3 nanomoles per liter (nmol/l)—the cut-off limit researchers used to determine if the procedure was successful. Two horses had basal testosterone concentrations above that limit, and another two more continued to display stallionlike behavior despite having testosterone concentrations below 3 nmol/l; the researchers considered the procedure in all four of those horses unsuccessful.

With laparoscopic castration, veterinarians cut off the testes' blood supply but leave them in place.

Photo: Courtesy Dr. Claire de Fourmestraux

The four horses were subsequently gelded using conventional methods, de Fourmestraux said. Data from microscopic evaluation of the testes available for three of those horses revealed a small amount of live tissue in either one or both testes, which could cause residual stallionlike behavior.

De Fourmestraux said the live testicular tissue could result from a surgical failure, such as incomplete transection of the vascular supply, or from “revascularization of the caudal (toward the back) part of the testis despite a complete transection.”

The surgery's failure rate, while low, led the researchers to conclude that laparoscopic castration would be only preferable for “horses that need to be stall-rested for various conditions … and horses not able to cope with general anesthesia and/or recovery.” They do not, however, recommend the procedure for normal stallions.

The study, “Evaluation of success rate of laparoscopic castration without orchidectomy in 32 mature horses,” was published in Equine Veterinary Education

Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.