Assessing physiological and behavioral responses over time in a group of laboratory Marshall beagles

Abstract

The aim of this study was to assess adaptive capacity in a group of purpose-bred Marshall beagles by means of a standard procedure that measures heart rate variability, salivary cortisol and behavior. Heart rate variability was measured with a Polar® heart-rate monitor and behavior was recorded with a video camera during two successive 5 minute observation periods; a ‘restrained’ observation period in which the dogs stood on a table while being restrained by a technician, and an ‘unrestrained’ observation in which the dogs were allowed to roam freely on the table. At the end of the standard procedure a saliva sample was taken to measure cortisol levels and compare with morning cortisol levels. A large variation was present in heart rate variability and behaviors observed in this sampled group of Marshall beagles. For the most part this variation could not be attributed to gender, age or previous experience in experimental studies, although more experienced dogs appeared to exhibit more tail between legs, which is considered fearful behavior. Physiological and behavioral responses over time were assessed for each individual dog using mean heart rate and the behavior tail between legs. Some dogs showed clear adaptive responses over time while others did not. Dogs that do not show an adaptive response over time may be at risk of poor welfare when exposed to a stressor, such as the environmental stimuli they may encounter when being used for laboratory research.