Lange, A., Waiblinger, S., van Hasselt, R. et al. 2021. Effects of restraint on heifers during gentle human-animal interactions. Applied Animal Behaviour Science 243, 105445.
Gentle human-animal interactions can induce positive emotions in cattle and enhance their welfare. We investigated whether a change in the animals’ perceived control over the situation influences their perception of the interactions. We compared the reactions of habituated heifers (n = 28) to stroking and talking in a gentle voice while they were restrained in a feeding rack as routinely practiced on farms (‘lock’) or free to move in an arena (‘free’), which allowed for a higher level of control over the situation and thus, probably a higher sense of agency. All heifers had a positive relationship to humans, i.e. freely accepted human touch, and were habituated to gentle human-animal interactions. Each animal was tested three times per condition and each trial comprised three phases: pre-stroking, stroking and post-stroking. Video recordings of the trials were analysed for behaviours associated with different affective states. We also assessed heart rate and heart rate variability (HRV). In line with our hypotheses, stroking and gentle talking led to longer durations of neck stretching, indicating a positive affective state in both conditions, with stronger effects in the ‘free’ condition. Longer durations of lower ear positions occurred during stroking primarily in ‘lock’; however, the ear positions differed already in the pre-stroking phase, suggesting that restraint itself affected the ear positions independently of the human-animal interactions. Decreased heart rates during stroking in ‘free’ suggest a calming effect of the gentle interactions when the animals were free to move, and HRV parameters imply a greater relaxation effect shortly after ‘free’ interactions. We thus conclude that heifers with a good animal-human relationship enjoy gentle interactions with humans also when they are restrained, but they seem to perceive them even more positively when allowed to move freely, possibly due to a higher degree of agency. Furthermore, the results of this study confirm ear postures as promising indicators of the affective states of cattle, but underline that external factors such as restraint can substantially influence ear positions and need to be considered in the interpretation of the results.