Efficacy of Intratesticular Glycerol Injection as Male Cat Contraception in Comparison with Two Surgical Approaches.

The objectives of the current study were to compare the use of a single bilateral intratesticular injection of 2 different volumes of glycerol 70% (0.5 and 1.0 mL) as a method of chemical sterilization and the application of 2 surgical procedures (orchiectomy and vasoligation). Animals were classified into 4 groups. Group 1:10 cats were subjected to a conventional bilateral orchidectomy. Group 2:6 cats were subjected to a bilateral vasoligation of the testicular blood supply without removing the testicles. Group 3:7 cats were subjected to a single intratesticular injection of 0.5 mL glycerol bilaterally and Group 4:7 cats were subjected to a single intratesticular injection of 1.0 mL glycerol bilaterally. Serum testosterone concentration (ng/mL) and average testicular length (cm) were measured just before (control) and weekly after orchiectomy (only serum testosterone concentration), vasoligation, and intratesticular treatment for 3 consecutive weeks. After 2 months from testicular vasoligation (group 2) and intratesticular administration (group 3 and 4), castration was performed for all cats. The epididymal sperm count and the histopathological findings were recorded for all groups after the orchidectomy. In group 2 serum testosterone level was significantly (P ˂ .01) decreased from (4.14 ± 1.10 ng/mL) before vasoligation (control) to (1.71 ± 0.34 ng/mL) 3 weeks postoperation. In group 4 a significant (P ˂ .01) decrease in serum testosterone concentration was recorded 2 and 3 weeks postinjection (1.41 ± 0.31 and 1.32 ± 0.21 ng/mL, respectively). There was a significant decrease in the testicular length 1 week after the vasoligation (group 2) and the testicular treatment (group 4) compared with preoperative controls of the 2 groups. Besides, the epididymal samples collected from groups (2 and 4) showed azoospermia. In conclusion, a bilateral intratesticular injection of 1.0 mL glycerol (70%) as a chemical method of tomcat sterilization can replace the surgical orchidectomy besides being less invasive and less traumatic and gave better results than using the intratesticular injection of 0.5 mL glycerol.