While the color of their coat may seem to be the most significant difference between the breeds of one of the most popular and beloved dogs, according to a study published in the journal Canine Genetics and Epidemiology, chocolate Labs have lifespans 1.4 years shorter than labs of other colors. That's a pretty significant gap amongst the breed.
Observing a sample of 33,320 different Labs living in the United Kingdom in 2013, researchers from the University of Sydney and the Royal Veterinary College at the University of London collected a random sample of data from 2074 of those dogs, studying the possible factors that could affect the lifespans of the popular breed. They found that the median longevity for all Labrador retrievers was 12 years. For yellow and black labs, life expectancy was 12.1 years while chocolate Labs typically only lived 10.7 years, along with a higher rate of skin and ear infections. That’s a 10% shorter life dictated simply by coat color.
“The relationships between coat color and disease may reflect an inadvertent consequence of breeding certain pigmentations,” professor Paul McGreevy, lead author of the study and chairman of VetCompass, said in a statement. “Because chocolate color is recessive in dogs, the gene for this color must be present in both parents for their puppies to be chocolate. Breeders targeting this color may, therefore, be more likely to breed only Labradors carrying the chocolate coat gene. It may be that the resulting reduced gene pool includes a higher proportion of genes conducive to ear and skin conditions.”
Chocolate labs were twice as likely to have ear infections and four times as likely to suffer from pyo-traumatic dermatitis, also known as hot-spot, a self-inflicted trauma to the skin incited by pain or irritation. This finding came as a surprise to researchers. But the study was also useful for uncovering other common health complications for Labs, such as obesity and types of ear infections. The study also found that males were significantly heavier than females, which had a statistical significance associated with neutering in males but not in neutering in females.
"We found that 8.8 percent of UK Labradors are overweight or obese, one of the highest percentages among dog breeds in the VetCompass™ database," Professor McGreevy said.
Overall, the most common health disorders and challenges amongst all Labs were as follows:
- Otitis externa - A specific type of ear infection, marked by chronic inflammation of the external ear canal
- Degenerative Joint Disease - This refers to arthritis or osteoarthritis, the result of gradual deterioration of cartilage in the joints.