Title: Manifestations of chronic and acute stress in dogs
Authors: Bonne Beerda, Matthijs B.H. Schilder, Jan. A.R.A.M. van Hooff, Hans W. de Vries
Published: 1997 in Applied Animal Behaviour Science
The researchers sought to review the behavioral, physiological and immunological stress reactions that had been previously published and add to that knowledge base with their own researcher. The authors applied auditory stimuli to 6 beagle dogs (3 “test” dogs and 3 “control” dogs) in a variety of intensities and length. Additionally, the authors used 10 beagle dogs to test for stress reactions during 50 minutes of transport and in an unfamiliar environment. The dogs had behavioral and physiological measurements taken throughout travel to the testing facility or during the auditory stress or control situations. The authors found a wide range of physiological responses to supposed stressful events. The researchers suggested that more research into stress parameters for various behavioral, physiological and immunological reactions is needed. Furthermore, the authors recommend recording a variety of stress reactions in order to reduce differences between individuals, breeds, age, gender or previous life experiences when attempting to quantify the welfare of animals exposed to stress.
Because this paper was about 50% literature review and 50% novel data, and because it was relatively old (17 years), I found this to be a highly, erm, fascinating read. Behavior researchers used to do some pretty sadistic things to dogs (i.e. shocking a dog with such a high voltage that the dog would, “urinate, defecate, scramble rapidly and vigorously around the compartment, emit high-pitched screeches, salivate profusely and roll their eyes rapidly with dilated pupils…”)! However flawed our currently animal research welfare laws are, they really are an improvement over…you know, no animal research welfare laws.
The literature review of this piece explained the historical efforts of animal behavior researchers to define which behaviors, physiological and immunological reactions in dogs were associated with stress. This research was probably fueled by the desire to define “stress” in dogs without any anthropomorphic influences. I thought it really highlighted the importance of “baby steps” in research: if you want to study stress in dogs, you must first define stress, determine how stress in manifested in the general population of dogs, and define measurable parameters of stress. Furthermore, if you want to say that stress is bad for dogs, you must first determine whether or not stress decreases the welfare of a dog! While these components might seem maddeningly insignificant, they are a requirement of understandable, reproducible, rigorous science.
The actual findings of novel research from this paper were not altogether interesting – which isn’t entirely surprising on account of the incredibly small sample sizes (6 and 10 dogs, respectively). The authors found a great variety in potential stress behaviors in these dogs, so they’re able to determine ranges for stress responses in any of the behaviors or physiological samples they measured. The authors also did not provide information about the dogs in regards to age, gender, neuter status, previous life experiences, etc., which could have offered some potential explanations for the variable stress reactions. It does highlight the need for more research into how individual differences between dogs could impact stress reactions and its welfare implications, I suppose.
Stress is an unavoidable part of canine life. If we can reduce stress on dogs, does this make their lives and thus welfare better off? This paper focused on the importance of linking stress to welfare implications. I am interested to read more about measurable stress reactions in companion animals!