Toward on-farm measurement of personality traits and their relationships to behavior and productivity of grazing dairy cattle.

There is growing evidence that animal personality is linked to a range of productivity traits in farm animals, including dairy cattle. To date, the methodology for assessing personality traits of dairy cattle is time consuming and often requires a test arena, which limits the opportunity for commercial farms to use personality traits of dairy cattle for individualized management. This study investigated whether personality traits of pastured dairy cattle, scored in short behavioral tests, are associated with daily behavioral patterns and milk production. Cows (n = 87) were exposed twice to each of 5 behavioral tests, where their responses to novel or putatively stressful situations were scored on an ordinal scale for investigative and reactive behavior toward a novel object and a novel human after exiting the milking parlor, response to restraint in a crush, avoidance distance from an approaching human in the paddock, and response to milking (step-kick behavior). Most behavior test scores were consistent over the 2 test repeats (using repeatability estimates, Mann-Whitney U test of difference between repeats, and Spearman rank correlation). Behavior test scores were subjected to a principal components analysis that revealed intertest relationships in 3 factors of correlated sets of test scores, interpreted as personality traits (fearful of humans, calm-investigative, and reactive to milking). Regression analyses determined how these traits were associated with daily grazing, ruminating, and lying behaviors, and milk production (after controlling for cow age, breed, lactation status, group, and climate variables). Cows that were more fearful of humans (high avoidance distance, reactive toward the novel human) had reduced lying time compared with cows that scored low on this trait. Cows that were more calm (during restraint) and investigative (toward the novel object) had greater grazing time, which likely contributed to their greater milk production compared with cows that scored low on this trait. Cows that were more reactive to milking produced less milk than cows that scored low on this trait. These results indicate that individual differences in daily behavior patterns and milk production of dairy cattle are associated with personality traits of cows, measured using several short behavioral tests. These methods may be useful for characterizing grazing dairy cattle on commercial farms, which could aid in understanding individual behavior patterns and provide opportunities for individualized management.