Labradors are more prone to being overweight in comparison to other breeds and scientists have now identified genetic variation that causes obesity in these dogs.
According to researchers, in developed countries, 34-59 percent of dogs are overweight -- a condition associated with reduced lifespan, mobility problems, diabetes, cancer and heart disease -- as it is in humans.
The findings, published in the journal Cell Metabolism, showed that one in four (23 percent) Labradors carry at least one copy of a variant of POMC -- a gene strongly associated with weight, obesity and appetite.
For each copy of the gene carried, the dog weighed an average 1.9kg heavier.
This explains why Labrador retrievers, also known as the favourite dog breed of Britain and the US, are more likely to become obese than dogs of other breeds.
"This is a common genetic variant in Labradors and has a significant effect on those dogs that carry it, so it is likely that this helps explain why Labradors are more prone to being overweight in comparison to other breeds," said lead author Eleanor Raffan from the University of Cambridge in Britain.
POMC gene is also known to be important in regulating how the brain recognises hunger and the feeling of being full after a meal.
"Further research in these obese Labradors may not only help the well-being of companion animals but also have important lessons for human health," the researchers suggested.
"Common genetic variants affecting the POMC gene are associated with human body weight," explained Stephen O'Rahilly, professor and co-director at Wellcome Trust-Medical Research Council in Britain.
The team analysed 310-pet and assistance dog Labradors. Independent veterinary professionals weighed the dogs and assessed their body condition score, and the scientists searched for variants of obesity-related genes.