Prior to castration surgery palpate the scrotum to ensure two descended testicles are present. Testes should be descended by 6-9 months of age. If not descended by 9-12 months of age, then the inguinal canal should be palpated to try and identify the cryptorchid testicles, and exploratory inguinal and/or abdominal surgery and testicular removal should be performed. Retention of inguinal or intra-abdominal (cryptorchid) testes increases testicular cancer risks. Within the context of CNR, you should consider where performing surgery to retrieve cryptorchid testes is a viable option in your project.

For the scrotal approach to castration, the scrotum must be aseptically prepared taking care not to damage the very sensitive skin. A sterile fenestrated drape should cover the aseptically prepared surgical site, with the testes visible through the fenestration and a sterile surgical kit opened in such a way so as to maintain sterility. Make a single bold incision on the ventral surface of the testicle through the skin and subcutaneous tissue, just lateral to the median raphe, approximately one third of the length of the testicle. Then follow an open or closed castration technique as described below.

For the pre-scrotal approach to castration, the caudal abdomen from the prepuce to the scrotum and surrounding areas to the medial thighs must be aseptically prepared taking care not to damage the skin. A sterile fenestrated drape should cover the aseptically prepared surgical site, and a sterile surgical kit opened in such a way so as to maintain sterility. The fenestrated opening of the surgical drape should be positioned between the prepuce and the scrotum, thereby covering the prepuce and scrotum to avoid contamination of the incision. Using the non-dominant hand, use pressure on the scrotum to push one testicle cranially into the pre-scrotal area. Make a single bold incision through the skin and subcutaneous tissue.. Then follow an open or closed castration technique as described below.

Once the testes have been gently exteriorised, there are again two options as to how to proceed with castration – open or closed castration techniques. The open approach where the internal spermatic fascia is incised, and the closed approach where the internal spermatic fascia is not incised. The open technique provides direct visualisation of the spermatic cord and is less likely to result in suture slippage and hemorrhage, but requires opening the peritoneal cavity and thus the consequences of any infection may be more significant.

When performing the scrotal approach, it is not recommended that the scrotum is sutured. A single interrupted suture may be placed in the dartos fascia, otherwise invert the scrotal skin and leave it alone. A small amount of fluid drainage is normal. With the pre-scrotal approach, a standard three-layer closure should be performed. Close the dense fascial layer with either interrupted or continuous sutures, the subcutaneous tissue layer can be closed with a continuous suture pattern, and the skin layer closed using buried subcuticular or intradermal sutures.