The study is among the first to measure, non-invasively, the production of a specific stress hormone produced by both the dog and its owner in response to stress in their home. The technique offers a new tool to assess animal welfare in a wide variety of non-laboratory settings, including high stress environments such as search and rescue and police-related pursuit.
Dr. Nancy Dreschel, a veterinarian who conducted the study as part of her work toward a doctoral degree in biobehavioral health, says, "There were no effects of the owners' behavior or the quality of the dog-owner relationship on the stress hormone response that we measured in the canine. However, the presence of other dogs in the household was linked to less pronounced stress reactivity and more rapid recovery of the thunderstorm-phobic animal."
The study is detailed in the current (December) issue of the journal, Applied Animal Behaviour Science, in a paper, "Physiological and Behavioral Reactivity to Stress in Thunderstorm-phobic Dogs and Their Caregivers." The authors are Dreschel, who is also an instructor in the College of Agricultural Sciences, and Dr. Douglas A. Granger, associate professor of biobehavioral health.
Thunderstorm-anxious dogs not only suffer classic signs of fear, including pacing whining and hiding, during a storm but also experience a 207 percent spike in the production of cortisol, a hormone also produced by humans during stress, the new study has shown.
Dreschel notes, "Thunderstorm anxiety in dogs is a very common problem with reports of 15 to 30 percent of pet dogs affected. The prevalence likely varies depending on location and the frequency and intensity of storms."
To measure the cortisol response in both the dogs and their caregivers, the researchers asked 19 dog-owner pairs, in which the dog had been diagnosed as storm-phobic, to listen to a 5-minute recording of a thunderstorm in their own home. The dog and its owner were both videotaped during the listening session. The dogs included five purebred golden retrievers, four other purebreds, including a corgi, a keeshond, a border collie and a Labrador retriever, and 10 mixed breed dogs over 15 pounds each.
Immediately prior to the listening session, both the dog and its owner provided a saliva sample in which the cortisol could be measured. The owner put a small cotton plug in his or her mouth to absorb saliva and the dog chewed on a small, absorbent cotton rope, which became saturated with saliva.
Twenty minutes after the 5-minute exposure to the storm recording, saliva samples were collected again from both owner and dog and, then once again, forty minutes after the listening session.
Dreschel says, "On average, the cortisol levels of the caregivers did not increase. The owners probably did not show signs of stress because they knew that the thunderstorm they were hearing was a recording. The dogs probably did not know it was a recording; although, one dog did fall asleep on the couch during the listening session."
Dogs that lived in multi-dog households had significantly less overall change in cortisol compared to dogs that lived in single-dog households. This finding corresponds to a less extreme reaction in dogs from multi-dog households and more rapid and complete return to normal following the listening session. However, dogs in multi-dog households started out with slightly higher cortisol levels, which could indicate that dogs living with other dogs are under more stress.
Dreschel does not recommend that the owners of dogs with thunderstorm anxiety get additional dogs. She notes that there was no difference in the behavioral response of the dogs in multi-dog households vs. dogs in single-dog households.
After the study, Dreschel offered behavioral recommendations to the participants. She notes that it is possible to de-sensitize dogs to storms but that it doesn't always work. Efforts to reduce the anxiety should be made, however, because of the toll on the dog and the owner. The behavior of storm-phobic animals can cause owners to experience lack of sleep, destruction of household items and furnishings as well as worry about their dog's physical and mental health.
The study was supported, in part, by the Penn State Behavioral Endocrinology Laboratory and Salimetrics LLC.