A critically appraised topic (CAT) to compare the effects of single and multi-cat housing on physiological and behavioural measures of stress in domestic cats in confined environments

BackgroundDomestic cats have evolved from solitary, asocial predators and whilst they may displaysocial behaviours, they can still exist as solitary survivors. Over-population andrelinquishment of pet cats are ubiquitous problems worldwide, and rehoming centres (alsoknown as rescues/ shelters) aim to ameliorate this by holding cats in confinement for avariable period until a new home is found. The provision of optimal housing for largenumbers of cats in close confinement, such as in rehoming centres, is therefore inherentlydifficult. Under these conditions there is the potential for individuals to develop signs ofphysical and psychological ill health, and thus experience compromised welfare. Availableinformation regarding housing practices that maximise welfare currently provides conflictingresults, and as a consequence there are no unanimous housing recommendations. The aim ofthis study was therefore to review the evidence on the impact of single housing compared tomulti-cat housing on stress in confined cats, as measured by physiological and/or behaviouraloutcomes. The review was conducted using a Critically Appraised Topic (CAT) format. Asystematic search of electronic databases (CAB Abstracts, Zoological Records and Medline)was carried out to identify peer-reviewed literature comparing single and multi-cat housing inconfined environments.ResultsA total of 959 papers were initially identified, six of which met sufficient criteria based ontheir relevance to be included within this review. All of the studies had significant limitationsin design and methodology, including a lack of information on how groups were assigned,inconsistent handling and enrichment provision between groups, and lack of information onthe socialisation status of cats.ConclusionsWhilst some studies suggested that single housing may be less stressful for cats, otherssuggested group housing was less stressful. Several other important factors were howeveridentified as potential mediators of stress within the different housing systems, andrecommendations based upon these findings are presented