Individuality of calves: Linking personality traits to feeding and activity daily patterns measured by precision livestock technology.

Animal personality has established connections with animal performance, resilience, and welfare which are related to stable behavioral patterns. Precision livestock technologies introduce the opportunity to measure these behavior patterns automatically and noninvasively. Thus, the primary aim of this study was to determine if personality traits in dairy calves measured via standardized personality assessments were associated with activity measured via a commercially available accelerometer. Secondary aims of this study were to investigate if personality traits were associated with feeding behaviors measured via an automatic feeding system (AFS) and with average daily gain (ADG). We characterized personality traits of Holstein calves (n = 49) utilizing standardized personality (novel environment, novel person, novel object, and startle) tests. Behaviors from these tests were summarized and 3 factors were extracted from a principal component analysis to represent calf personality traits: fearful, active, and explorative. Factor scores were regressed against behaviors from the accelerometer and AFS and with ADG. We found that calves that were more active were associated with taking more steps in the home environment, consuming more calf starter, and with reaching the benchmark of 1 kg of starter consumed in a day at a younger age. The trait active was also associated with greater ADG throughout the study. In addition, calves that were more explorative in the personality tests were associated with less starter consumed and lower ADG specifically during the weaning period. The findings of this research contribute to the existing literature by further establishing the links between personality traits and the daily behavioral patterns and performance of young calves. This study suggests the potential for using precision technology to assess and characterize personality traits, thereby enhancing their practical applicability on farms. Future research should focus on evaluating how personality traits, as measured through standardized assessments and precision technologies, correlate with deviations in behavior observed in dairy calves during stressors.