Epidemiology of surgical castration of dogs and cats in the United States.

OBJECTIVE

To estimate the prevalence of surgical castration among dogs and cats evaluated at private US veterinary hospitals and to determine the influence of sex, age, breed, geographic location, and prepaid wellness plan enrollment on the likelihood of castration.

DESIGN

Retrospective period prevalence study.

ANIMALS

320,172 cats and 1,339,860 dogs examined at 651 hospitals during 2007 Procedures-Univariate and multivariate analyses were used to compare prevalence among subpopulations for each species.

RESULTS

The overall prevalence of castration was 82% in cats and 64% in dogs. Prevalence increased significantly with age in both species. Among cats, males were slightly more likely to be castrated than females (prevalence ratio [PR] = 1.03) and mixed breeds slightly less likely than purebreds (PR = 0.99). Among dogs, males were less likely to be castrated than females (PR = 0.93) and mixed breeds more likely than purebreds (PR = 1.19). Prevalence was lowest in dogs in the Southeastern United States (61%). Dogs and cats on a wellness plan were more likely to be castrated than those not on a plan (PR = 1.33 and 1.18, respectively). Among commonly reported dog breeds, pit bull-type dogs (27%) and Chihuahuas (46%) were least likely to be castrated.

CONCLUSIONS AND CLINICAL RELEVANCE

Many young adult (1- to < 4-year-old) dogs (32%) were uncastrated, signaling a need to promote earlier castration. Outreach efforts should be directed toward owners of pets least likely to be castrated, such as male dogs, dogs of specific breeds (ie, pit bull-type and Chihuahua), and dogs in the Southeastern United States. Additional research is needed to evaluate the potential impact of wellness programs on an owner's decision to have his or her pet castrated.