• Posted April 25, 2022

Hair of the Dog: A Quick, Painless Stress Test for Pooches

The strange smells and sounds at an animal shelter can stress out even the most placid pup, and invasive tests to see if they need medicine to calm down only add to the anxiety.

So there's some good news for Fido in new research out of the Netherlands.

The study found that analyzing a single sample of a dog's hair gives an accurate measure of the stress hormone cortisol - a simple, pain-free alternative to collecting multiple samples of saliva, urine, feces or blood.

"[A shelter] really is a change in environment for most dogs, so often you do see a stress response," said lead researcher Janneke van der Laan. She is a doctoral candidate in the animal behavior group at Utrecht University.

Suddenly, van der Laan said, shelter dogs find themselves in a new place with unfamiliar noises and scents, and are separated from those they were attached to. It can lead to chronic stress, as well as behavior problems.

Her interest in the welfare and behavior of companion animals and her volunteer work at shelters converged in this small study, which was published online April 21 in the journal Scientific Reports.

In search of an alternative to invasive hormone tests, van der Laan and her team compared hair samples from shelter dogs to those of a control group of pups from private homes.

The researchers shaved a patch of hair on the dogs' necks to collect samples. Hair was collected when the dogs arrived at the shelter, again six weeks later, and then several times after they were adopted.

The study authors wanted to learn whether testing hair cortisol concentration would be as accurate as more invasive techniques, such as drawing blood. Cortisol is an arousal hormone that can indicate both positive and negative changes. Vets often measure it to determine whether an animal needs medication to calm down.

The takeaway: After six weeks in the shelter, dogs' cortisol levels rose significantly.

But the situation improved when they found new homes. After six weeks and then again after six months, their cortisol levels were similar to those when they entered the shelter.

"We were mainly interested in the shelter and immediately after adoption to see whether these two novel environments … would differ - that was an important question for us," van der Laan said. "And, also, we were very interested in the time period before the dogs came into the shelter, because that's the time period we often don't know much about."

Investigators have studied the impact of stress on dogs in other ways, van der Laan said, including looking at behavior, nighttime activity and hormone levels in urine samples.

If dogs are unable to adapt to their environment, long-term medical or behavioral problems may result, researchers have found.

"That really argues to try to lower stress levels as much as possible in an environment such as a shelter," van der Laan said.

Monitoring individual dogs is key, she said. Some adapt more easily than others, sometimes because of genetic profile or previous experiences.

The study included a control group of 20 pet dogs, along with 18 female and 34 male shelter dogs. On average, they were 3.8 years old.

The researchers noted that further study of hair testing for cortisol with more dogs, including those with different types of hair, is needed. German researchers have also studied hair testing.

Dr. Cassidy Cordon, a clinical instructor in veterinary medicine at Washington State University in Pullman, reviewed the new study findings.

She said, whether it's in a shelter or a temporary kennel situation, group housing is stressful for dogs.

Kennels are very loud and echo, and dogs can be affected by the stress of others who are barking, their sleep can be disrupted and even a change in routine can be stressful.

"It definitely has a huge, huge impact. Behavior-wise, it can make them more likely to lash out," Cordon explained. "It can also make them more likely to hole up and shell in, within themselves. So, they're kind of the shyer dog that you need to kind of almost give a confidence boost and get them to come out their shell again."

And, she added, "it's much like people - everyone kind of deals with it a little differently and dogs will, too."

Shelters can help ease some of this stress in a variety of ways, Cordon said, including playing music from dog-friendly stations that dampen some of the sound. Shelter workers can help them get as much enrichment as possible, while going slowly in helping them to adjust.

And after adoption, new families can help with the adjustment by establishing a routine for eating, walking and other activities and adhering to it, she suggested.

"The more predictable that you can kind of make your schedule, the easier and faster they will sometimes adapt," Cordon said.

More information

The American Kennel Club has more on how to tell if your dog is stressed.

SOURCES: Janneke van der Laan, doctoral candidate, Division of Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University, the Netherlands; Cassidy Cordon, DVM, clinical instructor, College of Veterinary Medicine, Washington State University, Pullman; Scientific Reports, April 21, 2022, online