The Caslick procedure of surgically closing the upper part of the vulva has been commonly practiced on broodmares for the past 60 years. The procedure evolved in an effort to treat what E. A. Caslick, DVM, had observed–the negative effect that air had on a mare’s reproductive system.

“Early in my experience with the treatment of genital infections, I recognized air as a factor,” Caslick wrote on the matter. “Mares that were placed on treatment (for genital infections) apparently became worse for a short period of time and then their condition remained quite constant. If these same mares were allowed a period of rest, an immediate improvement would be observed.”

Caslick suspicioned that the treatment-related introduction of air into the reproductive system was doing more harm than the specific treatment was doing good.

“The last case of this infection, I (Caslick) encountered was in 1927. At that time, I became firmly convinced that the admission of air into the vagina by constant treatment was detrimental, so I discontinued treatment of the mare and closed the dorsal (upper) half of the vulvar opening (the first “Caslick’s procedure”). In two months, this mare was normal and negative to culturing (for bacteria in the reproductive tract).”

In a 1937 volume of the Cornell Veterinarian, Caslick, a native of upstate New York and a graduate of Cornell’s College of Veterinary Medicine, reported his surgical technique and the thought processes that lead up to the technique’s development. Large parts of that original article will be quoted here as Caslick’s writings give great insight from a veterinarian who, in addition to mastering the science, also (and perhaps more importantly) mastered the art of being a veterinarian.

Wind-sucking, or more technically pneumovagina, was generally accepted as a potential problem in all racing femal