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[VIYS-19-05] Individual differences in daily sleep-like posture time among Japanese Black cows and its consistency
This study aimed to investigate the individual difference in daily sleep-like posture (SLP) time among in Japanese Black cows and its temporal and environmental consistency. In Experiment 1, 24 cows in a shed were monitored for their daily SLP time over a period of nine weeks. There was a significant difference in daily SLP time among individuals. Despite being kept in the same management, the longest cow (76.5 min/day) showed 56.8 min/day time difference compare to the daily SLP of the shortest cow (19.7 min/day). In Experiment 2, we examined the daily SLP time between two time points (2020 and 2021) and found that individual daily SLP time was consistent over time. In Experiment 3, individual daily SLP time was compared when they kept in sheds and grazed in pastures. The study found that individual daily SLP time were consistent across different management conditions. These findings provide that there is large individual difference in daily SLP time among cows and its difference would be consistent over time and under different managements.