Inbred pedigrees suffer from genetic diseases

Modern dog and cat breeds are not "natural" animals in the true sense of the word, according to Dr Adam West, senior veterinary surgeon at the Society for the Prevention of Cruelty to Animals (SPCA, Hong Kong). Instead, they are the end product of selective breeding, such as breeding for certain tasks or appearance.

"As a result, many pedigree breeds are inbred, and with a smaller gene pool comes higher rates of genetic disease than their mixed-bred relatives," West says. For example, a recent British study showed that the more than 10,000 pugs in Britain are so inbred that their gene pool is equivalent to only 50 individuals.

Another genetic term for this, West says, is the Founder Effect - only a small number of individuals from a larger population are used to found a new population. "These individuals may have unrepresentative genes and higher than average rates of deformities."

To make matters worse, the vet says, these issues may not be present or obvious in that cute puppy or kitten in the pet shop window, but may emerge only as the animal matures.

Improvements to Hong Kong's pedigree population are possible, the vet says. "But it can only come about through responsible breeding, legislation, co-operation and prompt reporting among breeders, veterinary surgeons and kennel clubs, and last, but certainly not least, help from responsible and well-informed consumers."

A responsible and well-informed consumer needs to be aware of, and avoid, "bad breeders", meaning those who breed and raise animals in unhygienic, stressful and overcrowded environments, where animal welfare is compromised. "These breeders often have limited knowledge of good breeding practices [or choose to ignore them] and do little to control breeding, which would actively breed out genetic problems inherent in many pedigree breeds," the vet explains.