Neutering Kittens Early Doesn't Lead to Heavier Cats, Study Finds

Nevena Nacic
by Nevena Nacic
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Longer life expectancy, reduced aggressiveness, zero spaying at home, and prevention of diseases are just some of the benefits of spaying or neutering your cat. Nevertheless, many owners decide to postpone sterilizing their kittens because spayed/neutered cats tend to eat more and gain weight easily. 


Obesity is commonly listed as the main disadvantage of neutering or spaying cats. The good news is that a new study has found no greater risk of weight problems in adulthood in kittens neutered at four months old compared to kittens neutered at six months old. 


The study, published in Vet Records, analyzed over 2,000 clinical records relating to 584 pet cats. Data showed no difference in body condition score (BCS) and bodyweight of kittens neutered at four months old or under, and those neutered at five or six months old, as they reached adulthood and senior years. 


For this study, the researchers used data from the Bristol Cats study at the University of Bristol. This longitudinal study follows kittens registered at 16 weeks old throughout their lifespan. 


Researchers also discovered that male cats usually weigh more and have a higher body condition score than female cats at any given time. Female cats showed lower body weight and body condition scores in summer and autumn, while male cats maintained a more consistent body weight and body condition score throughout all seasons. 


This study aimed to investigate the health outcomes of cats neutered before reaching puberty. Since neutering is a known risk factor for obesity in adult cats, some veterinary professionals are concerned that neutering kittens at younger ages may increase their chance of becoming obese in adulthood. 


This new study adds to a growing body of evidence that neutering cats at four months old does not compromise their welfare, while it also helps charities and vet practices alike to deal with the problem of feline over-population,” said Dr. Rae Foreman-Worsley, a feline welfare associate researcher for Cat Protection.


“By neutering cats from four months old, the veterinary profession can help to significantly reduce the number of unplanned litters and potentially homeless cats. At a time when financial constraints and issues with capacity are facing both owners and vets, a move to neutering cats at four months old may be an effective way to manage cat populations.”


Dr. Emily Blackwell, Senior Lecturer in Animal Behavior and Welfare, Director of Companion Animal Population Health, and Principal Investigator of the Bristol Cats study at Bristol Veterinary School, said, ”The Bristol Cat study collects information about the health, welfare, and behavior of cats across the UK. Data from Bristol Cats used in this research provides further evidence that neutering kittens at four months of age does not put them at greater risk of weight problems in adulthood than those neutered at six months.” 


“Neutering kittens at four months can be effective in preventing unwanted litters, and we are pleased to have helped to provide scientific evidence to inform neutering decisions,” Dr. Blackwell added. 


In light of these findings, researchers are now calling for more long-term studies to investigate the effects of pre-puberty neutering on adult cats’ weight. 


Neutering causes metabolic and hormonal changes in cats, leading to decreased energy expenditure and increased appetite. This can lead to weight gain and obesity if not properly managed. 


Veterinary professionals still consider neutering a risk factor for obesity in cats, but agree that more studies like this one are needed to better understand whether there is any link with neutering age. 


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Nevena Nacic
Nevena Nacic

Nevena is a freelance writer and a proud mom of Teo, a 17-year-old poodle, and Bob, a rescued grey tabby cat. Since childhood, she had a habit of picking up strays and bringing them home (luckily, her parents didn't know how to say NO). When she's not writing for her fellow pet parents, Nevena can be found watching Teo sleep. To her defense, that's not as creepy as it sounds!

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