Responses in a social isolation test are related to spontaneous home pen activity in dairy cattle

In order to be meaningful, tests of animal personality must not only be repeatable but also reflective of an underlying trait that is persistent outside of the test environment. In this study we investigated whether a well-used test of social motivation (SOC) in dairy cattle reflected their spontaneous home pen behaviours, e.g. did more sociable cows behave differently in the home environment? Ninety nine dairy cattle housed at the Dairy Research Centre, Leeuwarden (NL) were tested. Each cow was separated from the herd, with the herd confined at the opposite end of a 12 m runway. The subject was released and latency to rejoin the herd and agitation behaviours shown (such as vocalisations, frequency crossing a line 5 m from the herd, etc.) in a 5 min period were recorded. Home pen activity using tri-axial accelerometer based activity monitors and milk production traits were recorded for 40 days prior to the start of SOC testing (n=74 cows). Multiple regressions were used to test associations between behaviours relating to social motivation and long-term spontaneous home pen activity prior to testing. Most behaviours in the SOC test were affected by the cow’s lactation stage at testing and, after accounting for lactation stage at testing, were not significantly associated with spontaneous home pen behaviours. However there was a positive association for cows who frequently crossed the threshold line 5 m with shorter standing bouts, longer overall standing duration in a day, producing less milk per day and were less variable in their daily number of lying bouts (Model: R2 adj=0.19, F4,68=5.08, P=0.001; average standing bout duration t(64)=-3.08, P<0.003; average daily standing duration t(64)=2.63, P=0.011; average milk yield per day t(64)=-3.53, P<0.001; standard deviation of number of lying bouts per day t(64)=-3.01, P=0.004). This model explained 19% of the variation in the number of times the cow crossed the 5 m line. These results indicate a relationship between some SOC test responses and spontaneous home pen behaviour but may reflect an underlying activity motivation rather than sociability. The results suggest that measurement of reproductive stage and lactational status need to be taken into account when assessing some aspects of personality in cows and question the validity of the runway test in lactating dairy cattle.