Inconsistency in dairy calves’ responses to tests of fearfulness

Fear is generally agreed to be a major welfare concern. Although it is frequently studied and included in on-farm assessments, test protocols vary widely, and the literature provides limited evidence of reliability and validity of any specific test methods. We investigated the test-retest reliability of novel object and stationary human tests for dairy calves in a research setting, and for farm-level reliability of response to humans tests on farms. We found that latency to touch novel objects had moderate reliability, which was increased by using the same object for repeated tests; however, this practice may compromise the validity and generalizability of the results. Reliability of latency to contact humans varied among cohorts in the research setting. On farms, the proportion of calves retreating from the human was more reliable than was the proportion of calves making contact with the human. The presence of calves with symptoms of respiratory illness reduced reliability. We recommend that health status of calves be reported and ideally factored into analysis of fear tests, and that retreats rather than only approaches and/or contact be measured when assessing responses to humans. Further work is needed to validate the novel object test and determine whether some objects are more appropriate than others are.

 

Journal article: http://www.sciencedirect.com/science/article/pii/S0168159116302878