Do familiar group mates facilitate integration into the milking group after calving in dairy cows?

摘要

As dairy cows' needs and demands change over the different phases of their reproductive cycle, regrouping is common practice in dairy farming to facilitate management and handling. However, social instability associated with regrouping is known to have negative effects on the cows, including disturbances in their lying behaviour. In this study, we examined the effect of familiar group mates on lying time and lying synchrony in a dynamic group of approximately 50 early lactating dairy cows during 23 regrouping events. We focussed on 13 primiparous and 33 multiparous post partum cows during 24 h after their introduction to the group as compared to a matched control sample of resident cows. We hypothesised that freshly introduced cows would lie shorter and behave less synchronously with the group as compared to resident cows. Further, we hypothesised that lying duration and lying synchrony will increase with the number of familiar animals present and that these effects may depend on whether the familiarity was acquired early in life or only recently.