# Complications Following Orchiectomy in Stallions in Field Conditions: Descriptive Results and Predictors in a Study of 612 Cases

## TL;DR

This study examines complications after horse castration in field conditions and identifies risk factors like age, weight, and surgical techniques.

## Contribution

The study provides new insights into predictors of complications in field orchiectomy in stallions.

## Key findings

- 23.7% of 612 horses experienced at least one post-operative complication.
- Older and heavier horses had a higher risk of complications.
- The open surgical technique and use of the Henderson instrument increased complication rates.

## Abstract

The present work describes complications that occurred after orchiectomy performed in the field in male horses, as well as potential predictors for the development of such complications. The study is based on a dataset of 612 cases in male horses, operated in conditions of general veterinary practice by one of three experienced veterinary surgeons. At least one post-operative complication was recorded in 24% of the horses. The wide array of complications diagnosed in these animals included scrotal swelling/seroma formation, most often, and, less frequently, colic, continued stallion-like behavior, evisceration, funiculitis, hemorrhage and scrotal infection. This study identified that older or heavier horses, as well as horses operated by means of the open surgical technique or with the use of the Henderson instrument for achieving hemostasias, were at a higher risk of developing complications. The findings confirm that orchiectomy in horses, even when performed in field conditions, is, in general, a safe procedure. Veterinarians should take additional care when planning to operate on animals at higher risk or when using surgical approaches that increase the potential for the development of complications.

The objectives of this work were (i) to evaluate the incidence of complications in male horses after orchiectomy performed in the field, i.e., away from a veterinary hospital, (ii) to describe the post-operative complications that occurred in these animals and (iii) to study the potential predictors for the development of such complications. This study involved 612 animals, on which orchiectomy was performed. The operative part of the study was carried out by one of three experienced veterinary surgeons. Standard pre-operative procedures were followed. Orchiectomy was performed using one of three principal surgical techniques, open, semi-closed or closed, and hemostasis was achieved by means of one of the various procedures, specifically the use of the Henderson instrument, the use of the Reimer emasculator, the ligation of the testicular artery or combinations thereof. In cases of reported complications, these were verified and identified appropriately. At least one (any) post-operative complication was recorded in 145 horses (23.7%). The most frequently observed complication was scrotal swelling/seroma formation, which was observed in 130 animals (21.2% of all animals; 89.7% of animals with at least one (any) complication). Another six different complications were observed, specifically colic, continued stallion-like behavior, evisceration, funiculitis, hemorrhage and scrotal infection. The median age of horses with complications was significantly older than that of animals with no complications: 11 versus 9 years. Animals in which the open technique was applied developed post-operative complications more frequently (30.1% of animals thus operated); further, complications were observed more frequently in animals on which operations were performed by using the Henderson instrument (84.6% of animals) versus animals on which any of the various other procedures were applied (22.4%). In multivariable analysis, the following predictors emerged for the development of complications: the surgical technique employed, the procedure applied for hemostasis, older animal age, and heavier animal bodyweight. The findings confirm that orchiectomy in stallions, even when performed in field conditions, is, in general, a safe procedure. The identification of predictors suggests that veterinarians should take additional care when planning to operate on animals at higher risk or when using surgical approaches that increase the potential for the development of complications.