Intratesticular injection of a zinc-based solution for contraception of domestic cats: A randomized clinical trial of efficacy and safety

On day 120 the testis size of treated cats was decreased (P < 0.05). Azoospermia occurred in 8/11 (73%) cats, and penile spines were decreased in 6/11 (55%) and absent in 4/11 (36%) cats, and there were substantial reductions in male behavior. However, plasma testosterone concentrations (single samples collected at each assessment) were not significantly different between treated and control cats at any time point. Although additional studies are warranted, intratesticular injection of zinc gluconate might have potential as a permanent contraceptive for cats.