Personality traits of dairy cows: relationship between boldness and habituation to robotic milking to improve precision and efficiency

Research on the influence of personality on cattle management is gaining interest in the scientific community. In the context of Precision Livestock Farming (PLF), the Automatic Milking System (AMS) plays a key role, introducing a revolution in this field through intelligent process optimization to maximize efficiency and productivity. However, the biological mechanisms related to the animal's behavior and personality are poorly understood. This research investigates how boldness, a personality trait related to risk-taking, can affect heifers' habituation to the milking robot. Before calving, we investigated the behavioral reactions of twenty-three heifers alone in front of an unknown person (Individual Novel Human test- NHi), of a novel object (Individual Novel Object test- NOi), and another object while they stayed with other heifers (Group Novel Object test- NOg). Afterward, each heifer was video-recorded (focal sampling) during the automatic milking for the first ten milkings after parturition; videos were analyzed using the software BORIS©. Statistical analysis distinguished bold and shy subjects in each test and revealed that bold animals of NOi recorded less stepping rate (p<0.05) during the milking procedure, shy heifers of NH showed a higher kicking rate (p<0.05), while bold subjects of NOg spent less time in the robot (p<0.05) and fewer times pulled the teat cup off (p<0.05). These findings indicate that bold animals were less nervous during automatic milking, suggesting better habituation, and highlighting the importance of considering personality to improve welfare, precision, efficiency, and productivity.