Since the successful establishment of a fistula of the vas deferens in the ram by White, Larson & Wales (1959), various techniques have been devised for the collection of epididymal spermatozoa from bulls, rams and boars. Wierzbowski & Wierzchos (1969) list authors who have undertaken such work. Recently, we have developed a fistula method for the regular collection of epididymal spermatozoa from the rat.
Because of its extremely small diameter, the rat's vas deferens is unsuitable for cannulation and when brought directly to the surface of the skin, it soon becomes obstructed and covered by closure of the skin above it. It can, however, be anastomosed either to the small or to the large intestine by simple implantation and will generally remain open and continue to function indefinitely. Utilizing this principle to construct a fistula of the vas deferens, the following procedure has now been frequently undertaken in mature Sprague-Dawley rats (Charles River CD strain).