Sterilization of the Male Dog and Cat by Laparoscopic Occlusion of the Ductus Deferens

SUMMARY A laparoscopic technique was developed to sterilize adult and prepubertal male dogs and adult male cats. The animals were anesthetized, and each ductus deferens was identified intra-abdominally, using a laparoscope. Adult and prepubertal (16 weeks of age) dogs were sterilized by occluding 1 to 2 cm of the ductus deferens bilaterally, using an ancillary bipolar forceps and electrocoagulation. Adult cats were treated similarly or the ductus deferens was severed, using an accessory scissors device. Sperm counts in adult dogs decreased to zero within 48 hours of ductus deferens occlusion. Azoospermia also occurred in cats; however, live spermatozoa were detected in the ejaculates of some cats for as long as 120 hours after surgery. These observations indicated that, unlike in the dog, viable spermatozoa may ordinarily reside in the proximal abdominal portions of the reproductive tract of the cat. After sterilization, there was a nonsignificant (P > 0.05) tendency for testicular volume to decrease in dogs. Average and individual testicular volumes in cats were significantly increased (P < 0.05) after sterilization, which could have been related to increased epididymal fluid retention. Sterilization of prepubertal male dogs resulted in chronic azoospermia without influencing body weight or testis development. Laparoscopic sterilization had no effect on libido or copulatory ability in adult dogs or cats. Prepubertal dogs with bilaterally occluded ductus deferens developed penile erections and produced azoospermic ejaculates at ages comparable with sham-sterilized control dogs. Histologic examination demonstrated that spermatogenesis was normally active in all dogs and cats. Spermatocelic lesions were observed on the ductus deferens or epididymis in 33% of the test animals. Granuloma formation was confirmed in the ductus deferens by biopsy in at least half of the animals in each group, but these findings had no apparent compromising effect on general animal health. Ductus deferens epididymal fluid of all sterilized animals contained large proportions of morphologically deformed spermatozoa, the latter primarily characterized as sperm heads with detached flagella or severe cellular torsions. The laparoscopic sterilization technique resulted in rapid azoospermia in male dogs and cats without adversely affecting libido or testicular integrity. Such a procedure could have valuable application as a simple, practical means of sterilizing these species on a mass basis.