Vasectomy in Spotted Paca (Cuniculus paca)

Abstract

Background: Cuniculus paca is the second largest neotropical rodent. It is not endangered, but your habitat has been destroyed and the specie has been hunted, because of its prized meat. In this context captive breeding is an alternative to reduce the hunt. Then, adult male vasectomy is an interesting alternative for Cuniculus paca since the animal does not lose libido and maintain cyclicity of females into the enclosure. This technique is a method of sterilization which the vas deferens is surgically clamped, cut, or otherwise sealed and thus prevents the release of sperm when a male ejaculates. The aim of this study was to describe the vasectomy technique on a male spotted paca kept in captive.
Case: A captive adult male of Cuniculus paca, lived in Brazilian wild fauna breeding for scientifc research. It was maintained on precinct with no other animal, ate fruits, vegetables, tubers and rodent chow and water offered ad libitum. It was submitted to bilateral vasectomy to maintain reproductive behavior on bevy, but not impregnate females. The anaesthesia was performed using ketamine hydrochloride (25 mg/kg IM) and midazolam (0.5 mg/kg IM) as premedication, and isoflurane in open system by facemask diluted in 100% O2 for induction and maintenance. Immediately after induction, was performed epidural anesthesia using 4 mg/kg of lidocaine hydrochloride without vasoconstrictor associated in the same syringe with 0.2 mg/kg of methadone hydrochloride to promote analgesia. As the testes in this species are inside the abdomen, the surgical approach was made by paraprepucial skin incision and ventral midline abdominal incision. After access the cavity, the testes were located and the vaginal tunics were incised to access the vas deferens. After exposed, both were doubly ligated, sectioned and removed a segment of approximately 1 cm of each duct. Finally, the occlusion of subcutaneous and muscle layers were made using 2-0 absorbable and skin with 2-0 non-absorbable sutures. Postoperatively, benzathine penicillin (30,000 IU/kg IM once), tramadol (4 mg/kg IM once) and meloxicam (0.3 mg/kg SC SID for 3 days) were administered. Ten days post-surgery, the animal was fully recovered and after twenty days, it was transferred to enclosure of females. None were fertilized after vasectomy, and there was no change in reproductive behavior among individuals.
Discussion: Zoos and breeding have a problem when animal population increases too much, thus vasectomy is an important alternative to avoid this, because it does not lose sexual behavior, but cannot impregnate. The spotted paca presented intracavitary testicles without elevation Skin evidence to scrotum formation, however may also present inguinal regions testes beside penis or scrotum, most evident in reproductive season, similarly occurs in rats and agoutis. In the present case was performed bilaterally vasectomy to have satisfactory results for spermatogenesis reduction, confrming was indicated by some studies in rats and rabbits. Some studies in monkeys and rodents showed that after some time the spermatic cells decrease. In the present study sexual behavior and quality of patient ejaculate, were not completely monitor, to not interfere on management, but there was no female fertilized in a period of 1 year. This procedure showed to be feasible and an easy implementation for maintenance of the estrous cycle of females.

Keywords: Cuniculidae, reproduction, rodent, surgery, vas deferens.