Development of a Reversible Vas Deferens Occlusive Device. II Effect of Bilateral and Unilateral Vasectomy on Semen Characteristics in the Dog

Abstract

16 male beagles were used to study the effect of bilateral and unilateral vasectomy on the semen characteristics in the dog during research into the development of a reversible vas deferens occlusive device. Bilateral vasectomy of 8 dogs resulted in the immediate absence of spermatozoa from the ejaculate of 7 dogs indicating that the spermatozoa are stored in the epididymis and not partially in the ampullary region of the vas as in the human. No significant decrease in volume after bilateral vasectomy could be detected in the group as a whole but some individual dogs showed distinct changes. Unilateral vasectomy of 8 dogs resulted in an overall 50% decrease in total sperm count; again some individual variations were observed. These variations probably depended on the functional activity of the remaining testicle. After unilateral vasectomy volume decreases were noted with the amount of decrease proportional to the individual decrease in sperm count. There was no change in the percent of viable spermatozoa after unilateral vasectomy and there was no increase in abnormal sperm forms. Neither bilateral nor unilateral vasectomy appeared to affect the pH of the ejaculate. Details of the manual and artifical vagina collection methods and the vasectomy technique in the dog are described.(AUTHORS MODIFIED)