Individual consistency of dairy cows' activity in their home pen

The aim of this research was to investigate the long-term individual consistency of dairy cow activity in the home pen. Activity in a loose-housing barn was examined in 35 Holstein-Friesian dairy cows using an automatic monitoring system. Different amounts of activity could be distinguished by dynamic thresholds. Subsequently, the following categories of activities were calculated as mean daily values: number of high activity counts (N-HA), number of low activity bouts (N-LB), and mean duration of low activity bouts (D-LB). Category N-HA reflects locomotor behavior, and N-LB and D-LB reflect resting behavior. Recordings were repeated 4 times during a period of 2 lactations for 10 d each ( total observation time: 40 d). Effects of parity, week of lactation, and environmental conditions ( light intensity and ambient temperature) on activity were also assessed. Our results reveal a high degree of consistency in individual cow activity throughout 2 lactations. Repeatability (REP), calculated using covariance parameters, was high for all traits, although the REP of N-HA (REP = 0.62) was higher than the REP of N-LB (0.40) or D-LB (0.49). Parity, week of lactation, and environmental conditions had no significant effects on activity. In conclusion, our results indicate that activity of dairy cows in their home pen was highly consistent over time, and thus, could be considered as individual traits.