Validity aspects of behavioural measures to assess cows’ responsiveness towards humans

Abstract

Different measures reflecting the cows’ behavioural responses towards humans are used for the assessment of the human–animal relationship (HAR). Besides the established avoidance distance (AD), different handling tests, such as the tolerance to tactile interaction (TTI), release behaviour after restraint (RB), and qualitative behaviour assessment (QBA) during a human–animal interaction are used. However, uncertainties still exist regarding the measures’ validity, vulnerability to confounders or risks of observer bias. These aspects are addressed in the current study. AD, TTI, RB, and QBA were investigated on a research farm regarding (1) their relationships with an expected HAR improvement due to rewarding human-animal contact (here: manual provision of concentrate), (2) potential confounding effects of lactation status (before/after calving), (3) or an expectedly aversive event of claw trimming, and (4) the occurrence of expectation bias. Concerning objectives 1–3, different samples of cows (n = 13–29 out of 102 in total) were assessed repeatedly and differences in behaviour before and after manual concentrate provision, calving, and claw trimming were analysed using paired Wilcoxon tests; for the latter blinded videos were used. For objective 4, both for non-blinded live and blinded video assessments it was tested separately, whether assessments before and after claw trimming differed. After a 6-days period of manual concentrate provision, cows had lower ADs (p = 0.013, n = 27), responded less fearfully in TTI (p = 0.045, n = 27) and QBA (p = 0.026, n = 14), and by tendency in RB (p = 0.052, n = 27), supporting the measures´ construct validity, i.e. that all of them reflect changes in the relationship to humans after the cows experienced rewarding routine interactions. Neither blinded assessments before and one day after claw trimming (p = 0.489–1.0, n = 29), nor assessments before and after calving (p = 0.244–1.0, n = 13) differed significantly, suggesting that single routine procedures and physiological changes around calving do not confound assessments. Numerically, in non-blinded QBA after claw trimming cows were assessed less fearful than in blinded, possibly because the observer tried to avoid bias. Nevertheless, non-blinded live assessments did not yield any significant differences between HAR measures before and after claw trimming (paired Wilcoxon: p = 0.151–1.0, n = 15–29).