Do big dogs live less? New study brings answers – 01/17/2024 – Balance

Anyone who has or has had dogs has probably heard that smaller breeds are more likely to live longer and healthier lives.

“It’s a truth that we see as evident in everyday life, and that’s why we alert owners”, veterinarian Carla Alice Berl tells BBC News Brasil.

“A giant breed, weighing over 50 kg, usually lives for fewer years than a small one”, adds the specialist, who is the founder of Pet Care, a Brazilian chain with 33 units spread across the country and which serves 15 thousand animals per month.

“But a golden retriever, for example, has a greater chance of developing cancer than a shepherd.”

A new study, conducted by biologists, veterinarians and statisticians from seven American institutions, offers evidence about this perception.

The article, with title Dog size and patterns of disease history across the canine age spectrum (“Dog Size and Disease History Patterns Across the Canine Age Spectrum”), concluded that a dog’s size certainly affects its life expectancy.

Diseases with a higher risk of death, for example, are more prevalent in larger dogs.

“Larger dogs tend to live shorter lives. Additionally, different sizes of dogs tend to manifest different diseases (…) for example, large breeds die more frequently as a result of musculoskeletal and gastrointestinal problems,” the scientists wrote in the study.

While other factors did not affect the animals’ life expectancy, such as whether the dogs were pure breeds or mongrels, weight was considered a determining factor in reducing or increasing the risk of various illnesses.

Large dogs tend to develop bone, gastrointestinal, infectious, endocrine, neurological diseases, cancers and nose, throat and ear problems.

Smaller children, weighing less than 10 kg, are more likely to suffer from eye, heart, respiratory and pancreas-related problems.

There are also a smaller number of diseases, such as urinary and kidney diseases, whose occurrence does not vary according to weight.

The research, published in the scientific journal Plos One this Wednesday (17), was based on a compilation of information from 27,541 dogs of 238 breeds that live with their owners in the United States.

The data came from an open database powered by pet owners and used for scientific research, the Dog Aging Project.

The researchers, led by biostatistician Yunbi Nam, from the University of Washington, identified which diseases were most common among all these dogs.

Then, they cross-referenced the information with sex, size (dividing them into five weight categories), where they live and whether they are pure breeds or mutts.

For veterinarian Carla Alice Berl, from the Pet Care network, the study would have a slip-up.

“I missed information on specific breeds, as the situation varies too much among dogs of the same weight”, he points out.

“Brachycephalic dogs [conhecidos pela cabeça de formato achatado e o focinho encurtado]like bulldogs, are born with a lot of suffering, with various problems, such as respiratory problems.”

Therefore, according to the expert, these breeds, even though small, have a life expectancy similar to that of larger breeds.

Why do big dogs die earlier?

The study published in Plos One is dataistic. In other words, it is restricted to presenting the data found, without looking for reasons, biological or otherwise, for the difference in life expectancy of larger and smaller dogs.

“What happens to dogs is strange. Among mammals, usually the largest animals [como os elefantes, que morrem por volta dos 60 anos de idade, seis vezes mais que os cães], live longer, and this has to do with the rate of their metabolism. In theory, the same should happen with dogs”, biologist Frietson Galis, from the Natural Biodiversity Center, a natural history museum located in Leiden, in the Netherlands, tells BBC News Brasil.

Galis is the author of a study published in 2006 that became a reference in the field. In the title of the article, which is also one of the theoretical bases of the new research published in Plos One, the question is: “Do big dogs die young?”

Throughout her investigation, the scientist used a veterinary database to track which breeds live longer or shorter lives. She came to the following conclusion, according to herself: “It is linked to the artificial selection carried out by humans to obtain bigger dogs.”

According to their conclusions, breed crossings carried out by breeders over the last few centuries have favored animals that grow quickly, obtaining large sizes.

“As a result of the extreme rapid growth of these breeds, the animals developed diseases such as cancer,” says Galis.

What can owners do?

The rapid growth of large dogs’ bones means that the weight is harmful to them in several ways, such as putting pressure on their joints.

“For this reason, it is recommended that owners of these dogs do not feed them excessively, so as not to force the puppies to enlarge”, proposes biologist Frietson Galis.

Veterinarian Carla Alice Berl suggests that pet owners, particularly those with large sizes, control the animals’ food and weight – and this applies to dogs of all sizes.

“The ideal is to always maintain 15% below the breed’s average weight”, she says.

According to Berl, he calculates, based on his own studies and readings, that a thinner animal can live almost 20% longer.

“That could mean two extra years in a golden retriever’s life, or an extra year in a shepherd’s,” she says.

But the veterinarian warns that there is no point in just following this tip if other precautions are not up to date.

“If you want your dog to live longer, it is essential to vaccinate it, take care of its oral health, protect it from ticks and keep it active, with frequent physical exercise”, he recommends.