Scaredy-cat: Assessment of individual differences in response to an acute everyday stressor across development in the domestic cat

Abstract

A concern in animal welfare is the degree to which the animals in our charge experience stress during everyday procedures. Central to this is how to appropriately assess stress in relevant daily contexts. As one of the most popular companion animals worldwide, the domestic cat Felis silvestris catus is a good example. The cat may experience situations in daily life which can be considered stressful, such as confinement in a pet carrier for veterinary visits or to accompany its owners on holiday. It was therefore our aim in the present study to assess the response of pet domestic cats to brief confinement in a standard pet carrier during which we employed two behavioural and one non-invasive physiological measure thought to be indicators of stress. We investigated the presence of individual differences in 74 kittens’ responses before weaning (before 2 months of age) and the stability of these across development to adulthood in a subset of the same individuals tested after adoption in their new homes at 6, 12 and 18 months of age. Individuals were tested by placing them alone for 2 min in a pet carrier in an isolated room. Motor activity and vocalisation were continuously recorded, and eye and nose temperature were registered immediately before and after each test using a thermal camera. Statistical analyses showed stable (repeatable) individual differences for various measures of vocalisation and to a lesser extent for motor activity within and across age classes, but no relation between measures of the two. Thermographic measures of eye temperature showed no consistent pattern of thermal response to the test, and only weak and contradictory patterns of change in the temperature of the nose. In conclusion, we suggest measures of vocalisation to be a good indicator of individual differences of stress in response to such everyday procedures in the cat, although still needing validation from physiological measures. Facial thermography presently does not seem sufficiently reliable in this regard. Additionally, we emphasize the importance of conducting repeated tests across time to identify and develop reliable indicators of stress in whatever species.