Man's best friend is getting smaller

Australian pedigree dog lovers are choosing pugs and bulldogs over Labradors and German Shepherds, analysis by University of Sydney researchers shows.

Published in Canine Genetics and Epidemiology today the findings reveal Australian fans of purebred dogs now favour small, brachycephalic breeds – with shorter and wider heads – which are more susceptible to respiratory problems, skin and eye conditions, and digestive disorders. The data on numbers of each breed registered are published each year by the Australian National Kennel Council (ANKC), and suggest veterinarians may need to prepare to treat more dogs with these conditions.

The study investigated changes in the AKNC’s registration statistics between 1986 and 2013, examining trends in demand for Australian purebred dogs of various height, size and head shape.

The preference for smaller dogs correlates with a trend towards more high density living, says one of the lead researchers Professor Paul McGreevy from the University’s Faculty of Veterinary Science. Professor McGreevy co-authored the research with PhD candidate Kendy Teng.

“Changes in the types of dwellings Australians are buying may indicate the space available for dogs has shrunk. Moreover, the purpose of dog ownership has continued to shift from the early days of domestication, away from duties such as hunting and guarding properties, for which dogs are more likely to be larger, to pure companionship, which can be fulfilled by a dog of any size.”

Reasons behind the penchant for dogs with short, wide faces are less obvious but could reflect fashion, says Professor McGreevy.

“Other studies also indicate the infantile facial features commonly seen in brachycephalic dogs with their round faces, chubby cheeks, big eyes and small nose and mouth, stimulate feelings of affection in humans.”

Unfortunately, life expectancy among these popular breeds is an estimated four years lower than non-brachycephalic breeds. Brachycephalic Airway Obstruction Syndrome (BAOS) is particularly prevalent, often resulting in mild to life-threatening respiratory problems.

“A study in the UK shows half of owners of breeds susceptible to these health issues seem unaware of BAOS in their dogs,” says Professor McGreevy. “This implies owners did not make a fully informed decision when purchasing their brachycephalic dog, and that they may be unaware of treatment options when BAOS emerges, and that affected dogs may breed and pass the predisposition to BAOS onto future generations.”

Professor McGreevy and Kendy Teng co-wrote Trends in popularity of some morphological traits of purebred dogs in Australia with Dr Navneet Dhand and Dr Jenny-Ann Toribio, also from the University’s Faculty of Veterinary Science.

The AKNC data used in the study accounted for 16.5 percent of newborn puppies in 2014 therefore may not be representative of the general dog population in Australia. It is more likely to better reflect trends in Australia’s purebred population.