Are designer crossbreeds healthier than purebred dogs?

Labradoodles, puggles, dorgis, cavoodles and cavapoos: whatever name you use, designer crossbreeds are now impossible to miss on our pavements and in our dog parks.

As the health concerns linked with pedigree breeds have become better understood, many people have chosen these hybrid dogs instead. The idea is that designer crossbreeds have greater genetic variety and are therefore less prone to the conditions affecting purebred dogs.

Yet are these designer mixes genuinely healthier than their purebred relatives? Researchers at the United Kingdom's Royal Veterinary College examined that question in a paper published overnight.

Their study assessed three widely owned poodle crossbreeds - cockapoos, labradoodles and cavapoos - and concluded that they were neither healthier nor less healthy than comparable purebred dogs.

The team hopes its findings will enable prospective owners to make better-informed, evidence-based choices when choosing their next canine companion.

Designer crossbreeds

Most dogs living today were not selectively bred by people. Even so, over roughly 200 years, humans have developed more than 400 modern breeds, each with distinctive appearances and temperaments.

Several well-liked breeds, including the golden retriever, began as mixed-breed dogs. Many others, however, are "pedigree dogs" produced from a restricted genetic pool.

Supporters of purebred dogs argue that their health, behaviour and looks are more predictable. Many pedigree registries also no longer allow crossbreed dogs to be added.

However, the reduced genetic diversity of purebreds has, over time, contributed to extreme physical features and major welfare concerns in many dogs.

In response, some breeders have adopted "out-crossing": intentionally breeding dogs from two separate breeds. This approach aims to lessen inherited physical or behaviour issues and produce healthier puppies. The hope is that the young will be sturdier than either parent - a phenomenon also called "hybrid vigour".

This practice has contributed to the growth of "designer crossbreeds". Poodles in particular have been mated with other breeds, including:

• the cavalier King Charles spaniel-cross, called a cavoodle in Australia and a cavapoo in the United Kingdom
• the cocker spaniel-cross, called a spoodle in Australia and a cockapoo in the UK
• the labrador retriever-cross, known as the labradoodle. An Australian originally bred this mix to develop a non-allergenic guide dog.

Oodles of health issues?

The Royal Veterinary College research drew on a survey of approximately 9,400 people.

Some participants owned a crossbred dog: a cockapoo (spoodle), cavapoo (cavoodle) or labradoodle. The remaining owners had one of the purebred "progenitor", or founder, breeds: a cavalier King Charles spaniel, cocker spaniel, labrador retriever or poodle. Every dog was younger than five years old.

The researchers examined the assumption that designer crossbreeds are less likely to develop common disorders than their founder breeds.

They compared the odds of the 57 most frequent health conditions in the three designer crossbreeds against each of their founder (progenitor) breeds. Altogether, they carried out 342 comparisons.

Frequently reported health problems included ear and eye infections, diarrhoea and cruciate ligament rupture.

What did they find? Health outcomes were the same for poodle-cross dogs and comparable founder-breed dogs in 87% of cases.

Crossbreeds had a greater likelihood of a small number of disorders (7%). However, they had a lower likelihood of a small number (6%) of other disorders.

Taken overall, the findings provided no convincing evidence of "hybrid vigour" in these poodle crossbreeds. Nor was there evidence that purebred dogs were substantially healthier than designer crossbreed dogs.

What does this all mean?

Based on these findings, the authors said prospective owners deciding which dog to purchase should weigh up other considerations, including breeding conditions, temperament and the health of a puppy's parents.

The research considered only young adult dogs. Any health advantages from crossbreeding might not become apparent until later in life. Repeating the questions once the dogs reach old age would therefore help explain how designer crossbreeds age and reveal risk factors that could help them age well.

Crucially, the study examined only three crossbreed types, all involving poodles. Other designer crossbreeds could have better health outcomes than their purebred relatives.

For instance, flat-faced breeds such as pugs and French bulldogs are likely to suffer breathlessness, along with skin and eye conditions. Breeding these dogs with other breeds would restore a proper muzzle, with resulting health and welfare benefits.

Who could dogs be?

These results raise significant questions. Where do the animals sharing our lives come from? How are they bred, and is that information open and transparent? Are we comfortable with existing breeding practices? If we are not, what needs to change?

When we look for the ideal canine companion, it is only natural to want a dog that is healthy, lives a long time and is happy to share our home.

Those qualities benefit dogs, but they also benefit the people who care for them. A healthy dog brings lower veterinary costs. A longer life means more time together, while a dog that lives happily with us means less stress and a better quality of life for everyone at home.

So, how can we find such a dog?

In some European nations, dogs must satisfy rigorous physical, genetic and behaviour standards before they can be registered and used for breeding. Achieving this depends on nationally consistent licensing and properly funded enforcement - both absent in Australia.

Ultimately, we determine whether dogs are healthy, long-lived and happy. Breeders choose which dogs to mate. Dog lovers choose which puppies to buy. When we vote, we also influence how governments regulate the breeding industry.

For the wellbeing of our canine companions, I hope we make wise choices.

Mia Cobb, Research Fellow, Animal Welfare Science Centre, The University of Melbourne

This article is republished from The Conversation under a Creative Commons licence. Read the original article.