PSIV-A-1 - Assessment of Equine Acclimation to New Management Using Non-invasive Metrics

Abstract: Horses experience stress during transportation, handling, and changes to the environment which result in negative welfare for the animal. Finding valid methods to measure stress non-invasively can assist in understanding equine welfare. Our objective was to investigate equine stress to a new environment through non-invasive measures. We hypothesized that horses’ stress would decrease over time with repeated exposure to a single handler and novel holding stock. Seven horses were introduced to a novel farm with a week of acclimation to their stall to serve as their baseline. Blink rate, thermal imaging, and salivary cortisol were collected in the stall and again in the stock on days 2, 3, 5, 7, 10, 14, 17, 21, and 28 with d 1 being one week following arrival to the farm. Blink rate was counted for three minutes, then eye temperature of the left eye was taken using thermal imaging, and lastly salivary cortisol was collected using cotton swabs introduced into the horse’s mouth for 30 seconds on each side. Using linear regression, we found that blink rate decreased by 1.7 blinks for every day of handling (P = 0.001). For every degree of eye temperature in the stall, stock eye temperature increased 0.28 degrees Celsius showing that stress was potentially higher in the stocks (P = 0.043). Additionally, eye temperature in the stock increased by 0.09 degrees Celsius for each day of handling (P < 0.01). There were no differences found in salivary cortisol (P = 0.43). In conclusion, blink rate decreased but eye temperature increased over time, creating conflicting outcomes. Further studies are needed to validate the non-invasive measures of stress and their implications for horse welfare in new environments.