Chemical Sterilization: A Safe Alternative for Dogs?

In an effort to reduce stray dog populations, researchers are looking at the safety and effectiveness of chemical sterilization as an alternative to surgery. In this article, Raffaella Leoci looks at the use of calcium chloride dihydrate (CaCl2) as a chemical sterilization agent that could help to make neutering programs more cost and time efficient. With the right formula and application, CaCl2 is highly effective, and the author concludes it could be a major step forward in reducing dog overpopulation.

Around the world, wherever people breed and keep companion animals, pet overpopulation is a major issue. Though trap and neuter programs can make an impact, they are expensive and difficult to administer. One solution to the inefficiency of traditional neutering programs is to use chemical sterilization methods. Researcher Raffaella Leoci, a DVM and specialist in pet reproduction based in Italy, argues in this blog that calcium chloride dihydrate (CaCl2) may be the right chemical for the job. As a chemical castrating agent, CaCl2 is a commonly available salt used for various medical applications. Though her study is contemporary, it is not the first. Leoci notes that “the first published reports of using CaCl2 to sterilize animals date back to 1977 and 1978 […] at Washington State University, Pullman. But the procedure was neglected for decades until researchers […] in India began exploring its use in companion animals. Their research provided good indications that calcium chloride could indeed be an ideal chemical sterilizing agent.” Building on this foundation, the author sought to clarify how CaCl2 might work on a wider scale, trying to understand the best concentration and solution of the chemical, as well as the welfare implications and impact on canine behavior.

In her study, Leoci found that “a 20% concentration of CaCl2 in an alcohol solution (called “Calchlorin”) met all our requirements – azoospermia over the 12 month study and a significant drop in testosterone and associated sex-linked aggressive and mating behavior.” This on its own is good news, but her explanation also provides more cause for optimism. “The procedure was also safe, quick and easy to administer. The dogs even showed little reaction to the intratesticular injection,” she noted. “There may be slight pain sensation when the needle pierces the skin, but the dogs are unlikely to experience pain from within the testis.” How does this procedure compare to surgery? Though Leoci states that “basic attention” has to be paid to proper injection technique, if the procedure is done smoothly it “requires no medical recovery and carries no risk of secondary infections – providing a great improvement over the welfare implications of surgical castration.”

Of course, one study cannot fully predict outcomes across the board, and Leoci notes that to further assess the use of CaCl2, more data from the field must be gathered to “evaluate its performance in a variety of environmental conditions with varied practitioner skill levels, dog sizes and temperaments.” However, for animal advocates who are interested in more effective population control programs, even this one study is certainly some cause for celebration. “An alternative method to surgical sterilization that is effective, easy to administer, safe, and affordable would offer immense benefits, allowing animal welfare organizations, public health programs, and governments to reach further with limited resources,” Leoci says, and we are sure that many animal advocates engaged in companion animal advocacy would agree.

Original Abstract:
Could chemical sterilization be an affordable solution to keeping stray dog populations under control? Raffaella Leoci, DVM, PhD, is a researcher at the University Bari Aldo Moro in Italy and a specialist in pet reproduction. She is the lead author of two articles published in Acta Veterinaria Scandinavica on chemical sterilization of dogs using calcium chloride, which identified the most effective concentration and the optimal solution. In this guest post she tells us why she thinks use of calcium chloride sterilization could be the answer to stray overpopulation.