Measuring emotions in dairy cows: Relationships between infrared temperature of key body parts, lateralised behaviour and milk production

The emotions of cows could be reflected in their body temperature, productivity and behaviours. We tested whether there is a positive correlation between non-invasive infrared temperature (IRT) and right-side laterality (presumed to indicate anxiety), and negative correlation with milk production in a large group of randomly selected cows. Lactating cows (n = 171) were examined individually in 3 consecutive one-month periods. Each month maximum infrared temperatures of the head and coronary bands of forelimbs were recorded daily for 6 days and lateralisation was determined from ten daily forced lateralisation tests. In the first month rightlateralised cows had higher IRT in their eyes than left-lateralised cows. The absence of an association between IRT and laterality in periods 2 and 3 suggests habituation to the test conditions. Right lateralised cows waited for longer before milking than left lateralised cows, and limb IRTs were negatively related to the waiting time before milking. We conclude that the connection between lateralised behaviour and eye IRT in this study provides evidence of differences in cows' emotional response to the forced lateralisation test.