Personality is associated with feeding behavior and performance in dairy calves

Abstract

Performance varies considerably at weaning, perhaps in part because it is associated with the personality traits of the animals. Our objective was to identify calf personality traits using standardized tests and determine whether these were associated with measures of feeding behavior and performance. Fifty-six dairy calves were housed in 7 groups of 8 calves each with access to an automated milk feeder and ad libitum access to water, starter, and hay. We measured starter DMI and the number of unrewarded visits to the automated milk feeder during each of 4 periods: prestep (full milk allowance; 7-41 d of age), step (milk allowance reduced to 50%; 42-50 d of age), weaning (51-54 d of age), and postweaning (55-68 d of age). At 27 and 76 d of age, each calf was subjected to 3 novelty tests: novel environment (30 min), human approach (10 min with an unknown stationary human), and novel object (15 min with a black 140-L bucket). During each of the tests, 7 behaviors were scored: latency to touch and duration of touching the human or object, duration of attentive behavior toward the human or object, number of vocalizations, number of quadrants crossed as a measure of activity, and duration of inactivity, exploration, and playing. Data were averaged across ages and then across tests. Principal component analysis revealed 3 factors (interactive, exploratory-active, and vocal-inactive) that together explained 73% of the variance. Calves that were more exploratory-active began to consume starter at an earlier age and showed greater starter dry matter intake during all experimental periods and greater overall average daily gain. Calves that were more interactive and vocal-inactive had more unrewarded visits to the milk feeder during initial milk reduction. We conclude that personality traits are associated with feeding behavior and performance around weaning.