Shelter Dogs' Stress Levels Can Be Measured Through Cortisol Levels in Their Hair, Study Shows

Two dogs nuzzling in front of bright blue sky and grassTwo dogs nuzzling in front of bright blue sky and grass
Getty Images

A recent study showed the stress levels in dogs' hair during a several month period.

Dogs experience high levels of stress before, during and after they stay at a shelter, according to a recent study.

Cortisol, a stress hormone, has been used to measure stress levels in various animals as well as humans.

"In addition to the cortisol measurements in hair, we also measured cortisol values in the dogs’ urine. This gives a short-term picture while the hair measurements show the long term," researcher Janneke van der Laan explains in the study.

The researchers examined the hair through a process called the “shave-re-shave method.” This means that hair was taken from the same location on the body for each data collection, shaving the area and then allowing new hair to grow in-between collection dates, according to the study.

Researchers examined 52 dogs from a shelter in the Netherlands during four instances, including right before admission, six weeks in the shelter, then six weeks and six months after their adoption. 

"We took daily measurements in the shelter for over a year. After adoption, the new owners - after clear instructions - cut the dogs hair and sent it to us," Van der Laan said. "They were helpful and enthusiastic, and were very interested in what their dog had experienced before adoption.” 

To create a control group, cortisol levels were compared to those of 20 domestic dogs that were similar in terms of breed, age and sex.

Ultimately, there is no major difference between the cortisol levels of dogs when they enter the shelter and the control group of domestic dogs. 

Researchers found that after six weeks in the shelter, cortisol levels in the pups’ hair appear to have increased by one-third — on average from 16 pg/mg to 21.8 pg/mg, according to the study.

In the six-week and six-month time periods after adoption that were measured, data showed lowered cortisol levels, which is in the direction of the average numbers collected at the time of the dogs’ shelter admission, according to the study.

Related Stories