Short communication: Feeding station behavior of grazing dairy cows in response to restriction of time at pasture

The short-term behavioral adaptation of cattle to time restrictions at pasture is poorly understood. This research explored the FS behavior of dairy cows during the first grazing session of the day (0800–1200h) in response to daily restriction of time at pasture. Six groups of 8 multiparous Holstein–Friesian cows (470±47kg, 35±9days in milk) were strip-grazed on a perennial ryegrass (Lolium perenne L.) pasture for either 4h after each milking (2×4), one period of 8h between milkings (1×8), or 24h excluding milking times (control, CTL). Daily herbage allowance was 0.07kg DM/kg live weight/day for all treatments. Cows were not fed supplements. Six cows per group were equipped with IceTag 3D motion sensors and GPS collars to measure the total distance walked, and the number of FS per min, and to allow calculation of the step length while eating. Bite rate (bites/min) and eating time (min) were determined for these cows. Bites per FS, velocity of walking while eating (m/min), total number of FS, total distance walked while eating (m), and area explored while eating (area of FS×total number of FS) were calculated. The velocity of walking while eating and the number of FS per min were also determined at 4 fixed times during such a grazing session. No difference in the number of FS per min and bites per FS was found between treatments, although cows in 1×8 had the greatest velocity of walking while eating for the first 200min of the grazing session. Eating step length, velocity of walking while eating, total number of FS, distance walked while eating and area explored while eating were the greatest for cows in 1×8. Cows in CTL showed the lowest values for the total number of FS. The results of this experiment demonstrated that dairy cows reacted to restrictions of time at pasture mainly by changing locomotion behavior (step length, velocity of walking while eating, and distance walked while eating), which led to considerable changes in the area explored while eating. This study of foraging behavior contributes to the understanding of eating and locomotion behavior of dairy cows in response to restrictions of time at pasture.