Vasectomy is a procedure used for sterilization that entails removing a small section of the vas deferens (the tube that carries sperm from the testicle to the urethra, during ejaculation). This is a technical surgery that requires accurate knowledge of the anatomy of the spermatic cord and meticulous attention to detail. If the wrong tissue is removed or too small a portion is removed, fertility may remain or may return at some time after surgery. After vasectomy is performed, testosterone levels will remain the same, along with all other male traits (drive, interest in breeding, male behaviors). Sperm production is also maintained, it is just that the sperm cannot get out of the testicle to the urethra.
Vasectomy sites can sometimes recanalate restoring flow of sperm through the urethra. Recanalization of the vas occurs in almost 2% of human vasectomies overall (early or late combined), the species where the procedure is done most. In cattle and sheep, between 1- 5% recanalate, either early or late.
Complications of vasectomy include sperm granuloma formation which can cause pain in the scrotum requiring a second, more difficult surgery to remove them or development of tumors at the ends of the vasectomy site, which are usually benign but can become malignant if not noticed early in their development. Hemorrhage into the scrotum and infection of the surgery sites may also develop, requiring treatment.
Vasectomized dogs are just like intact dogs in all behaviors (desire to breed, roam, potential for aggressive behavior) and their ability to transmit disease (Brucella, herpesvirus, transmissible venereal tumor). Any owner that has a vasectomized dog must be responsible enough to control these behaviors exactly the same as an intact male. Even if they are sterile, they can and will still actively seek out and breed bitches. A possible concern for owners of vasectomized dogs is that after the procedure is performed they may relax their handling behaviors, perhaps allowing an accidental breeding to occur. Not only can this transmit disease between the male and female (brucellosis or herpesvirus) but if recanalization has occurred it may result in pregnancy as well.
For the above mentioned reasons, it is this author’s recommendation, that if owners want their dogs to have exposure to gonadal steroids for a few years to gain their benefits, they should just leave the dog intact for 3-5 years, treat him like an intact male with all the protections that go with it, and then neuter him. After 3-5 years, there are more down sides (benign prostatic hyperplasia, prostatitis, perianal adenoma formation, testicular tumors), to being intact than benefits.
Courtesy of Dr Cheryl Lopate of REPRODUCTIVE REVOLUTIONS