Abstract
Background:
Castrating stray dogs using a low-cost, easily performed, and less invasive method can help address public health issues.

Aim:
This study assessed the effectiveness of a single intratesticular dose of zinc gluconate in inducing sterilization in adult dogs.

Methods:
18 adult dogs were divided into 3 groups. The GΙ (zinc gluconate) had an injection volume of 0.2-1 ml per testis; the GП (surgical), in which the testicular blood supply was tied off by double transfixing ligatures; and the GШ (control), in which the testicle was injected with normal saline.

Results:
Clinically, there were scrotal ulcerations in the GΙ and testicular swelling, surgical incision dehiscence, and infection in the GП, while in the GШ, testicular edema was the only finding. Testicular diameter values were dramatically (P≤0.05) reduced at day 30 in GП (1.48±0.13) compared with GΙ (2.49±0.14) and GШ (3.10±0.13). The serum testosterone level was significantly (P ≤ 0.05) lower in animals of GП (1.17 ± 0.26) at day 30 compared to animals of GΙ (2.55 ± 0.23) and GШ (3.53 ± 0.28). Histopathological sections in GΙ revealed atrophy of the tubuli recti epithelium and degeneration of the seminiferous tubules despite the presence of Leydig cell clusters. While in GП, the main characteristic findings were seminiferous tubule degeneration, Leydig cell atrophy, and vacuole degeneration of the basal and Sertoli epithelium.

Conclusion:
The injection of buffered zinc gluconate into the testicles caused tissue loss that produced sperm with little impact on testosterone production and had no effect on the general health of animals.

Key words: Castration; Dogs; Surgical; Testicular blood vessels; Zinc gluconate.