Intestinal Biopsies in the Standing Horse: What, When and Why?

Introduction
Intestinal biopsies are a valuable diagnostic aid for a variety of gastrointestinal diseases in the horse. Collection of full-thickness biopsies during exploratory laparotomy is ideal; however, cost limitations and wound complications in the post operative period limit the usefulness of this technique, and most veterinarians rely on biopsies obtained from the standing horse.

Rectal biopsy
A rectal biopsy involves obtaining a full-thickness mucosal and submucosal specimen from the rectum under standing sedation using endometrial biopsy forceps. The horse is restrained (e.g. stocks) and a gloved hand is inserted into the rectum and emptied of faeces. The biopsy forceps are cupped in the gloved hand and inserted approximately 30 cm into the rectum. The rectal mucosa is grasped between the thumb and forefingers at the 10 o’clock or 2 o’clock position and carefully placed into the jaws of the biopsy forceps. The forceps are closed and fingers are then passed around the forceps blade to ensure that the mucosal specimen is totally separated from the rectum before withdrawing the forceps. The specimen is carefully removed from the forceps with a needle and placed into 10% buffered formalin. A portion of the rectal biopsy should also be submitted for bacterial culture in cases of acute or chronic diarrhoea. Some blood is usually present on the rectal sleeve following the procedure; however, complications have not been reported and prophylactic antibiotics are not required. […]