Lefebvre SL1, Yang M, Wang M, Elliott DA, Buff PR, Lund EM.
Effect of age at gonadectomy on
the probability of dogs becoming overweight.
J Am Vet Med Assoc. 2013 Jul 15;243(2):236-43.
Summary
The authors of the above study compared 1,930
dogs that were spayed or neutered (gonadectomy) to 1,669 sexually in tact dogs
to evaluate the tendency of the spayed or neutered dogs to become
overweight. They also looked at
the effect of age at the time of gonadectomy to see if that had an effect on becoming
overweight. All dogs were patients at Banfield Pet Hospitals, giving the
authors a consistent data retrieval system. Follow-up on all animals was for a
period of greater than or equal to 10 years.
The authors found that spayed
or neutered dogs were statistically more likely to become overweight compared
to sexually in tact dogs. However,
this was found only for the first 2 years after the spay or neuter. Age at
gonadectomy and sex of the dog did not affect the tendency to become
overweight.
An additional interesting
finding in the study was that both groups of dogs (gonadectomy vs. sexually in
tact) had a surprisingly high percentage of overweight individuals. In the
sexually in tact dogs, 37% became overweight over time, and in the
gonadectomized dogs, 66% became overweight. Also, large breed dogs were more
likely to become overweight in this study.
Commentary
This was a well-designed and
executed study of a large population of dogs. The diagnosis of being overweight
seemed arbitrary since no objective criteria were used other than body condition
scores, but veterinarians performing routine examinations of the dogs were the
ones making the overweight diagnosis.
Looking at the entire group
of dogs (3,599), over half of them were diagnosed as being overweight. Beyond
the effect of gonadectomy, this study illustrates the larger problem of obesity
in pets. Whether being fed too much, or exercising too little, a high
proportion of pets in the US are at an unhealthy weight which is likely
affecting their quality of life and resulting in secondary health problems.
More research is needed to investigate the causes of obesity in pets and how it
can be effectively managed.
What are your thoughts about this study and about the
more global problem of pet obesity? Post comments either here or on facebook
(Dr. Stephen Birchard, Veterinary Continuing Education).