Designer crossbreed dogs, such as Cavapoos, Cockapoos, and Labradoodles, have surged in popularity across the UK, with many prospective owners drawn to them by the perception that crossbreeds are healthier than their purebred ancestors. This belief is based on the concept of 'hybrid vigor,' or heterosis, which suggests that offspring from the intentional crossing of distinct breeds should exhibit improved health and vitality. However, scientific evidence supporting the health benefits of designer crossbreeds is limited, prompting a need for more robust research to inform potential dog owners.

In response to this knowledge gap, a recent study surveyed 9,402 owners of both designer crossbreeds and their progenitor breeds—Cavalier King Charles Spaniels, Cocker Spaniels, Labrador Retrievers, and Poodles. The aim of the study was to provide evidence-based data on the relative health of designer crossbreeds compared to their purebred parents. Specifically, the authors hypothesized that designer crossbreeds would have lower odds of developing common health disorders compared to purebreds, a hypothesis driven by the assumption of hybrid vigor.

To assess health outcomes, the study used a cross-sectional survey approach, collecting data on 57 common health disorders, such as hip dysplasia, ear infections, and skin conditions. The analysis was designed to control for potential confounding factors such as dog age, sex, neuter status, and owner demographics (age and gender), which could otherwise skew the results.

The findings of the study challenged the prevailing belief in the health superiority of crossbreeds. Of the 342 comparisons made between designer crossbreeds and their purebred progenitors, 86.6% (296 comparisons) showed no statistically significant difference in the likelihood of developing common health issues. This indicates that, in the vast majority of cases, the health outcomes of crossbreeds and purebreds are largely similar.

In 7.0% of the comparisons (24 comparisons), designer crossbreeds had higher odds of developing certain health issues, while in 6.4% of cases (22 comparisons), they had lower odds. This mixed outcome suggests that while there are slight differences in health outcomes for specific conditions, designer crossbreeds are neither overwhelmingly healthier nor more prone to illness than purebreds. For example, while some crossbreeds may have lower odds of developing conditions like hip dysplasia, they may have higher odds for other conditions like ear infections or certain skin disorders.

The study’s results imply that the widely held notion of hybrid vigor in dogs may not be as strong as commonly believed. The limited differences in health status between designer crossbreeds and their purebred progenitors suggest that health should not be the sole factor driving acquisition decisions. Instead, potential dog owners are encouraged to focus on a variety of other important welfare factors. These include the breeding conditions of the dog (to avoid puppy mills or irresponsible breeding practices), the temperament of both the parents and the offspring, physical conformation, and the overall health history of the dog’s lineage.

Moreover, the study does not suggest that crossbreeds are at a higher risk of poor health compared to purebreds. The findings also emphasize that, for both crossbreeds and purebreds, responsible breeding practices play a crucial role in promoting canine health and welfare. Selecting reputable breeders who prioritize health screening for hereditary conditions in both the purebred and crossbreed populations can help minimize the risk of acquiring a dog with significant health problems.

In summary, while the belief in hybrid vigor has fueled the demand for designer crossbreeds, this study provides a more nuanced understanding of the health of these dogs. It shows that, for the majority of common health conditions, there is little difference between crossbreeds and purebreds. Prospective dog owners should therefore base their decisions not just on perceived health advantages, but also on other crucial factors such as breeding ethics, temperament, and the health and welfare of the dog’s parents.

Read full study here: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0306350