Long term effect of neutering age on body condition score and bodyweight in domestic cats

Background
Neutered cats are more predisposed to obesity. However, limited research has explored whether body condition score (BCS) and bodyweight vary across lifestages as a function of age at neutering.

Methods
Longitudinal clinical records of BCS (n = 2410) and bodyweight (n = 2073) were paired with age at neutering and other owner-reported auxiliary information before analysis using cumulative link mixed-effects models and linear mixed models to explore which factors influence BCS and bodyweight as cats age.

Results
BCS and bodyweight were age dependent, increasing until 9 years of age and then declining. No differences in BCS or bodyweight were found between cats neutered at 4 months or younger, 5 months or 6 months. Cats neutered at 7‒12 months experienced a less rapid age-related increase in bodyweight and BCS. Females had lower bodyweight and BCS than males, with differences more pronounced in the summer and autumn. Longhaired cats had a lower BCS than shorthaired cats, but hair length was not significantly associated with bodyweight.

Limitations
It was not possible to measure welfare impacts or incorporate diet and lifestyle measurements.

Conclusion
Cats neutered prepubertally showed no difference in bodyweight or BCS as cats aged compared to cats neutered at 5 or 6 months. Cats neutered at 7‒12 months had a lower risk of bodyweight and BCS gain overall. Postneutering weight management advice is recommended for all cats, and monitoring should utilise a combination of both BCS and bodyweight, particularly for longhaired cats.