Everything You Need to Know About Equine Castration: A Practical View on Different Approaches & Complications

Castration is probably the most commonly performed surgical procedure in equine and is associated with a fairly low percentage of complications. Nevertheless, complications following castration is the number one reason for lawsuits against equine practitioners. Some of the complications are inherent to the surgery and difficult to rule out. However a part of the intra- and post-operative complications can be avoided by a good preparation, good knowledge of the male anatomy and an adequate technique. 

A thorough clinical exam should precede every surgical intervention. Febrile horses, horses that cough or have diarrhea or horses with purulent wounds are not good candidates for elective surgery. The presence of two testicles in the scrotum should be verified. Horses with only one testicle should be sedated and the scrotum and inguinal area should be palpated. When deep palpation does not reveal the missing testicle, a rectal exam and/or transabdominal ultrasound should be performed. Transabdominal ultrasound has been shown to be a sensitive and specific technique for localizing undescended testes. In cryptorchid horses, failure of right and left testicular descent occur with nearly equal frequency. However, in one study the left, undescended testes were more frequently located in the abdomen compared to the right undescended testes. Inguinally located testes can be removed by routine castration under general anaesthesia whereas abdominal cryptorchids are better referred to a clinic. When the presence of testicular tissue cannot be ruled out, hormonal assays or laparoscopy may help in the definitive diagnosis.

Horses can be castrated standing under sedation and local anesthesia or in lateral or dorsal recumbency under general anesthesia. The approach can be scrotal by two parallel incisions on either side of the raphe or by scrotal ablation, or inguinal by incision directly over the superficial inguinal ring. Regardless of whether the horse is castrated while standing or recumbent, or whether the approach is inguinal or scrotal, the techniques used for castration are the open, closed and half-closed techniques depending on whether the common vaginal tunic is opened or not. It is important to know that the closed technique has no advantage over the open technique in preventing evisceration if a ligature is not applied to the cord proximal to the site of transection.  [...]