Chocolate Labradors die younger because of their colour, scientists find
Chocolate Labradors die more than a year younger than black and yellow ones because of their prized colour, according to new research.
They are bred for the hue of their coat which reduces the size of their gene pool – increasing the risk of disease, say scientists.
Earlier this year the Labrador was voted Britain’s favour- ite dog. Now, for the first time, a study has found its colour effects longevity.
Chocolate ones are more rare but have become popular family pets. The yellow and black varieties are commonly used as guide or gun dogs respectively.
The analysis of more than 33,000 Labrador retrievers taken to UK vet practices found the chocolate dogs were particularly prone to ear infections and skin disease.
It extracted data on disorder and mortality from a random sample of 2,074 (6.2 per cent) of the dogs.
Professor Paul Mcgreevy, of the University of Sydney, explained: “The relationships between coat colour and disease may reflect an inadvertent consequence of breeding certain pigmentations.
“Because chocolate colour is recessive in dogs, the gene for this colour must be present in both parents for their puppies to be chocolate. Breeders targeting this colour 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.”
The three different colours are often associated with different roles.
The yellow has become associated with Guide Dogs for the Blind, the black with gundog work and the chocolate dogs with pet homes and the showring.
But in Britain, and possibly elsewhere, non-chocolate Labradors live for an average of 12.1 years.
This is over 10 per cent more than those with chocolate coats, reports Canine Genetics and Epidemiology.
The prevalence of ear inflammation, or otitis externa, was twice as high.