Mood swings in cows: Cognitive and physiological assessments

Summary

How to know whether cows are moOody?

Emotions and moods colour the lives of dairy cows. However, farmers cannot easily identify how their cows are doing because cows cannot verbalize how they feel. Scientifically, animal mood can be assessed by measuring individual optimism using a Judgment Bias Task. This task was developed specifically for dairy cows in our study but remains too time-consuming to be used on farm. More practical indicators of mood must, hence, be identified to allow farmers to monitor their cows’ mood, for example using physiology. In this project, cows were housed under reference conditions before being brought under contrasted conditions to supposedly induce either positive or negative moods; and several non-invasive physiological variables were assessed: hair cortisol, heart rate variability and milk fluctuations. None of the variables varied according to the pleasantness continuum outlined by the housing conditions, suggesting that they do not allow to discriminate positive from negative moods. However, cows with a fearful character had greater milk fluctuations when moved to the unpleasant housing conditions. Certain cows may thus be more vulnerable to specific conditions and milk fluctuations may help detect lower mood in cows.