Surgical castration results in the complete loss of fertility and stallion-like behavior through the total removal of both testes and epididymides. Stallions reach sexual maturity between 12 and 18 months of age.

Castration can be performed using different techniques.

Firstly, a distinction is made between castration performed in the standing horse under standing sedation and castration performed in recumbency under general anesthesia. Secondly, castration is classified as either an open or a closed technique. covered and uncovered castration are distinguished.

During normal development, the testes descend into the scrotum and are usually palpable within the scrotum a few days after birth. At the latest by 12 months of age, both testes should be palpable in the scrotum; otherwise, the condition is referred to as cryptorchidism. Depending on the location of the affected testis or testes, cryptorchidism is classified as abdominal cryptorchidism (the testis or testes are located within the abdominal cavity) or inguinal cryptorchidism (the testis or testes are located within the inguinal canal).

In open castration, both the scrotum and the connection to the abdominal cavity, the so-called vaginal process (processus vaginalis), are incised. The spermatic cord is crushed but not ligated, and the testis is then removed. This technique is commonly performed in the standing horse under sedation in younger stallions (up to 3 years of age). An advantage of this method is that no suture material is used, thereby eliminating the risk of suture material intolerance. However, this technique carries a risk of intestinal or omental prolapse, as the communication with the abdominal cavity is opened and small intestine or omentum may prolapse through the inguinal ring. In addition, the risk of hemorrhage is increased due to the absence of vascular ligation.

In closed castration, the scrotum is incised and the spermatic cord is both crushed and ligated with suture material in order to close the communication with the abdominal cavity and the associated blood vessels, thereby minimizing the risk of intestinal prolapse and hemorrhage. The placement of suture material, which is usually absorbable, increases the risk of unilateral or bilateral spermatic cord fistula formation. A spermatic cord fistula represents a wound-healing disorder caused by the suture material, which in these cases is not absorbed but instead recognized as a foreign body and rejected. This condition is often associated with swelling of the castration sites, fever, and non-healing surgical wounds.

When closed castration is performed under general anesthesia, the skin (scrotum) can be closed with sutures. Wound-healing complications, such as spermatic cord infections or infections of the castration wounds, may occur following both open and closed castration due to bacterial contamination.

Stallions affected by inguinal or abdominal cryptorchidism may be castrated under general anesthesia via the inguinal canal. In this procedure, the testis or testes are either removed directly from the inguinal canal or the abdominal cavity is entered through the inguinal canal, allowing the testis to be exteriorized and removed. In such cases, the inguinal canal must be sutured closed, and the skin is also closed. Alternatively, under either standing sedation or general anesthesia, an abdominally retained testis may be ligated endoscopically (laparoscopy) and left within the abdominal cavity.

At our clinic, castration is performed exclusively under general anesthesia using a closed technique.