Aim: Castration is almost the only way to reduce pet overpopulation. Dog overpopulation and stray dogs are global issues that harm both public health and animal welfare. As a result, the current study sought to provide alternate surgical castration approaches, if viable. Also included is a comparison between surgical and pharmacological castration.
 
Methods: Under the anaesthetic effect of intravenous (IV) 2% xylazine HCl (1 mg/kg) and 5% ketamine HCl (10 mg/kg), standard surgical castration and intra-testicular injections were done. The dogs were positioned dorsally recumbent. Using a 24-gauge, 2.4 cm sterile needle, a 10% formalin solution was placed within the testes (2 ml / testis).
 
Results: Clinical follow-up in the formalin group demonstrated edema and redness in the scrotum and prepuce following injection, according to the findings. In the formalin group, a dog developed a little scrotal ulcer. In the current study, blood testosterone concentrations in the formalin and surgery groups fell considerably at the end of the experiment compared to day 0. Cortisol levels were elevated at the start of the trial and thereafter returned to normal. Histopathological evaluation of the testes in the formalin group, showing necrosis of seminiferous tubules. In addition, oxidative stress markers rose in both the formalin and surgical groups and steadily reduced towards the conclusion of the trial. Histopathological evaluation of the testes in formalin group showing necrosis of seminiferous tubules
 
Conclusion: Based on the seminal and biochemical assessments in this work, intratesticular injection of 10% formalin (2 ml) seemed successful for chemical sterilization of dogs and applicable on a broad scale.