Current state of spay/neuter programs in United States and effect on overall animal numbers

Abstract

Surgically altering (spaying/ovariohysterectomy and neutering/orchidectomy) of companion dogs and cats is a culturally enforced phenomenon in the United States. This is unusual, almost unique to our culture and represents the largest experiment of long term health consequences of a surgical procedure ever performed. Over the past 5 decades, spaying and neutering pets has become a normal, expected part of responsible pet ownership. Veterinarians have achieved remarkable market penetration of this technique with an estimated 80% of cats and 69% of dogs altered.1 Spay/neuter programs - defined as intentional, formalized efforts to have large numbers of dogs and cats altered – have historically been shelter-based and performed on institutionally owned animals, but there is a shift underway towards organizations providing these services to privately owned animals in under-resourced communities. These programs have unquestionably had an impact on dog populations, although evidence in cats is less compelling. Limitations of existing population estimates for dogs and cats are substantial. Nonetheless, impacts are directionally consistent and indicate reductions in unwanted dogs and cats in the US. While this is positive, there have also been some unexpected negative consequences of widespread spay/neuter programs, including impacts on availability of adoptable animals available through rescue groups and shelters, as well as impacts on proportions of breeds available in certain geographic regions and cities.