Obesity Rates in Sterilized Dogs Vary by Breed Size and Age at Spay/Neuter, Research Shows

Dogs are among the most popular pets in the world, and many owners choose to sterilize them for various reasons.

Sterilization is the surgical removal of the reproductive organs, also known as spaying for females and neutering for males. It can prevent unwanted pregnancies, reduce the risk of certain diseases and cancers, and improve the behavior of some dogs.

However, it can also have some negative effects on the health and well-being of dogs, such as increasing the risk of obesity.

Obesity is a serious problem for dogs, as it can lead to various health issues such as diabetes, arthritis, heart disease, and reduced lifespan.

According to a recent study published in the Journal of the American Veterinary Medical Association, obesity rates in sterilized dogs vary by breed size, sex, and age at sterilization.

The study used data from more than 155,000 dog records from U.S. Banfield Pet Hospital clinics and included both purebred and mixed-breed dogs.

Breed Size Matters

(Photo : BENJAMIN CREMEL/AFP via Getty Images)

The study found that the risk of obesity differs with body size. Sterilized small dogs face the highest risk, while giant-breed dogs have the lowest.

Surprisingly, large breeds like Labrador retrievers, German shepherds, and golden retrievers exhibit obesity rates akin to small dogs.

Additionally, the research highlights that the timing of sterilization plays a crucial role. Sterilizing dogs at one year of age tends to result in a lower risk of obesity.

However, the optimal timing varies by breed size. Notably, large dogs sterilized at three or six months face a higher risk of obesity, a significant finding.

The researchers speculated that the early removal of sex hormones may affect the growth and metabolism of large-breed dogs differently than small-breed dogs.

They also suggested that other factors, such as genetics, diet, exercise, and environment may influence the obesity risk in different breeds.

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Males Have Higher Risk Than Females

Another surprising finding of the study was that when all other factors are equal-breed, size and age at sterilization-males have a higher risk of obesity than females, contrary to common assumptions.

The researchers explained that this may be due to the different effects of sex hormones on appetite regulation and energy expenditure in males and females.

Valerie Benka, Program Director at the Alliance for Contraception in Cats & Dogs, and a member of the multidisciplinary research team that performed the study, said that this finding challenges the stereotype that female dogs are more prone to weight gain after spaying.

She added that owners should be aware of the potential risks and benefits of sterilizing their dogs and consult with their veterinarians to make informed decisions.

Future Research

Benka said that this study is part of a larger project that aims to provide more evidence-based information on the effects of spaying and neutering dogs.

She said that they are working on a publication leveraging this data to analyze the outcomes of specific breeds.

Additionally, they will explore the correlation between sterilization, obesity, and cranial cruciate ligament injuries in dogs.

She also expressed her gratitude to the Morris Animal Foundation for supporting this project and enabling them to publish their papers with open access so that everyone can view them.

This research is important for improving the health and welfare of dogs and their owners, according to the researcher.

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