The idea that many of our cute pups are also affected by their genetics has been confirmed by new research. The study found that most dog breeds have high levels of inbreeding. Over time, inbreeding can contribute to various health problems and expensive vet bills for larger dogs.
Many dog breeds aren't blessed with robust health due to long-running breeding programs that use closely related relatives to pick for the traits most liked in a breed The pug or bulldog are well known for their smushed-in faces, which can lead to breathing problems and other issues. The aim of the new study is to get a sense of how much inbreeding is affecting the dog population in general.
They used a genetic database made up of results from commercial DNA tests of nearly 50,000 dogs to do this. They used the average genetic similarity of dogs within a breed to estimate their level of inbreeding on a percentage scale from 1 to 100. They compared their results to data from previous studies of smaller groups of breeds.
They estimated that the average level of inbreeding within these breeds was 25%, or about the amount of genetic similarity you would see between two siblings. It doesn't bode well for a population of animals that rely on genetic diversity if two members of the family are close. You can see a higher risk of hereditary disorders or other conditions influenced by genes if the levels are far lower.
The study author said that the data from other species and strong breed predispositions to complex diseases highlight the relevance of high inbreeding in dogs to their health.
Bannasch and her team used insurance claims for non-routine vet visits as a proxy for dog health, by cross-checking their findings with data from a pet insurance database. They found that dog breeds with higher levels of inbreeding were more likely to need vet care. Non-brachycephalic dogs were more healthy than brachycephalic dogs.
Previous studies have shown that small dogs live longer than large dogs, but no one had previously reported on morbidity or the presence of disease. According to the study, if dogs are of smaller size and not inbred, they are much healthier than dogs with high inbreeding.
The team's findings were published.
Bannasch and her team found some dog breeds that were less inbred. These dogs are better protected because of a large population and because they are still bred for various jobs, not just for their appearance. Not all breeds with high inbreeding seemed to be bad.
The authors say that careful management of breeding populations is needed to preserve the existing genetic diversity of all these dogs. The authors caution that even though some breeders have started to outcross their dogs in hopes of improving the genetic health of their populations, they have to be careful to ensure that they will really improve diversity.
There has been some recognition of the problem, but dog breeding groups and organizations are hesitant to admit many flaws with the current state of things. The Netherlands has passed strict laws on the breeding of brachycephalic dogs, and some veterinary groups have started to plead with people not to buy popular breeds like the pug.
