New Study: Are Mixed Breed Dogs Really Healthier Than Purebreds?

Labradoodles, puggles, dorgis, cavoodles, cavapoos: whatever you call them, there's no escaping the explosion of designer crossbreeds parading along our streets and through our dog parks these days.

People have flocked to these hybrid dogs as the health problems associated with pedigree breeds became more widely known. As the theory goes, crossbreed designer dogs are more genetically diverse, so are less likely to suffer the health issues plaguing purebreds.

But are these designer mixes actually healthier than their purebred cousins? This was the question researchers from the United Kingdom's Royal Veterinary College set out to answer in a new paper published overnight.

The study focused on three common poodle crossbreeds: cockapoos, labradoodles and cavapoos. It found they were no more or less healthy than their pure-breed counterparts.

The researchers hope the findings will help dog owners make more informed, evidence-based decisions when selecting their next furry friend.

Designer crosbreeds

Most dogs alive today were not bred under human control. Regardless, humans have created more than 400 modern dog breeds in around 200 years, each with their own looks and temperaments.

Some popular dog breeds, such as the golden retriever, have mixed-breed origin stories. However, many are "pedigree dogs" bred from a limited gene pool.

Advocates for purebred dogs say they have more predictable health, behaviour and appearance. And many pedigree registers no longer permit the inclusion of crossbreed dogs.

Over time, however, this lack of genetic diversity among purebreds has led to

extreme body types and serious welfare problems for many dogs.

To overcome these issues, some breeders have turned to "out-crossing": deliberately mating two dogs from different breeds. The goal is to dilute inherited physical or behaviour problems, producing healthier puppies. The aspiration being that the offspring will prove more robust than their parents, also known as "hybrid vigour".

This has led to a rise in "designer crossbreeds". In particular, poodles have been crossed with other breeds, such as:

the cavalier King Charles spaniel-cross, known as the cavoodle in Australia and cavapoo in the United Kingdom the cocker spaniel-cross, known as the spoodle in Australia and cockapoo in the UK The labrador retriever-cross, known as the labradoodle. This mix was originally bred by an Australian, to create a non-allergenic guide dog.

Oodles of health issues?

The research from the Royal Veterinary College involved a survey of about 9,400 people.

Some owned a cross-bred dog – either a cockapoo (spoodle), cavapoo (cavoodle) or labradoodle. Others owned one of their purebred "progenitor" or founder breeds – either a cavalier King Charles spaniel, cocker spaniel, labrador retriever or poodle. All dogs were aged under five years.

The authors tested the assumption that designer crossbreeds have less chance of suffering common disorders compared to their founder breeds.

They compared odds for the 57 most common health disorders across the three designer crossbreeds with each of their founding (progenitor) breeds. In all, 342 comparisons were made.

Common health issues included eye and ear infections, diarrhoea, and cruciate ligament rupture.

And the results? The poodle-cross dogs and comparable founder-breed dogs shared health outcomes 87% of the time.

Crossbreeds were more likely to experience a small number of disorders (7%). But they were less likely to experience a small number (6%) of other disorders.

Overall, there was no compelling evidence in these poodle crossbreeds of "hybrid vigour". There was also no evidence purebreds were significantly healthier than the designer crossbreed dogs.

What does this all mean?

The authors concluded that, given their results, prospective dog owners wondering which dog to buy should consider other factors such as breeding conditions, temperament and the health of a puppy's parents.

The study focused only on young adult dogs. Crossbreeding may bring health benefits that don't emerge until later in life. So a study that repeats these questions when the dogs are seniors would help us understand how designer crossbreeds age, and identify risk factors so we can help them age well.

Importantly, the study only looked at three types of crossbreeds, all involving poodles. Other designer crossbreeds may experience better health than their purebred cousins.

For example, flat-faced dogs such as pugs and French bulldogs are likely to experience breathlessness and skin and eye problems. Crossing these breeds with other dogs would reintroduce a proper muzzle to their face, bringing health and welfare advantages.

Who could dogs be?

All this raises important questions. Where do the animals in our lives come from? How are they bred, and is this information transparent? Are we OK with current breeding practices? And if not, what must change?

It stands to reason that, when searching for the perfect canine companion, we want one that will be healthy, long-lived, and happy to live with us.

These attributes are good for the dog. They are also good for their people. A healthy dog means fewer vet bills. Longer-lived equals more time shared together, and living happily with us translates to less stress, and a better quality of life for everyone in the home.

So how do we find that dog?

Some European countries mandate that dogs must meet strict physical, genetic and behaviour requirements before being registered and used for breeding. This requires a nationally consistent licensing regime and well-resourced enforcement – both of which are lacking in Australia.

What ultimately controls if dogs are healthy, long-lived and happy is us. Breeders decide which dogs to mate. Dog lovers decide which puppy to buy. And when we vote, we help decide how governments regulate the breeding industry.

For the sake of our canine friends, I hope we choose well.

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

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