Calcium chloride (CaCl) has been used as a nonsurgical alternative to castrating male dogs and cats. Dr. Raffaella Leoci of the University of Bari in Italy is the lead author of the studies elucidating the optimal formulation for using CaCl in alcohol to sterilize dogs through testicular injection. Her research team has conducted a controlled experiment comparing intratesticular vs. intraepididymal injection of CaCl in alcohol. Results were published in the journal Theriogenology.
Sperm are produced in the testes, and move to the epididymis for maturation and storage. Either structure could be a target for chemical sterilization by eliminating sperm. Dr. Leoci’s research on 148 dogs has shown that both injection methods resulted in an absence of sperm in semen. As expected, intratesticular injections significantly reduced testosterone levels since testosterone is produced by the testes. The reduction in testosterone is usually preferred so that hormone-associated behaviors such as marking and sexual behavior in dogs and cats is reduced.
The intraepdidiymal injection of CaCl in alcohol had no impact on testosterone levels. This injection was more difficult and required ultrasound guidance, but might be an option when nonsurgical sterilization is desired that preserves hormones, such as for large breed dogs. And perhaps one day, this nonsurgical method might even replace vasectomy for men!