Temporal feed restriction and overstocking increase competition for feed in group-housed dairy cattle

Dairy cows are often overstocked. Some managers are now also using ‘slick bunk’ management to save on feed costs, but this reduces the time cows have access to feed. Both practices may increase competition and affect feeding behaviour in cows. The aim of this study was to determine the effects of temporal and spatial restrictions on the feeding and competitive behavior of group-housed cows. Using a replicated Latin square design 48 Holstein cows were randomly assigned to groups of 6 cows. Groups were tested as overstocked at the feeder (2:1 cows:feed bin) or not (1:1 cow:bin) and provided feed access for either 14 or 24 h/d. DMI, feeding time and rate were measured for 24 h and 2 h following fresh feed delivery for the last 4 d of the 7 d periods. Displacements were recorded for 2 h after delivery of morning feed (peak feeding period) and 2 h following afternoon milking. DMI tended to decline when temporal access was restricted (27.0 vs. 25.7 ± 0.5 kg/d), but was not affected by overstocking (26.4 ± 1.9, mean ± SD). Temporally restricted cows spent less time feeding (190.9 vs. 207.9 ± 6.1 min). Overstocked cows that were also temporally restricted had greater feeding rates during the day (156 vs. 137 ± 4 g/min) and especially during the peak feeding period (175 vs. 146 ± 4 g/min) compared to cows that were not restricted. In the peak period, overstocked cows had reduced DMI (3.0 vs. 3.4 ± 0.1 kg/h) and feeding times (20.8 vs. 25.8 ± 1.0 min/h) and increased feeding rates (161 vs. 138 ± 4 g/min). Cows with restricted temporal access had greater DMI (3.9 vs. 2.6 ± 0.2 kg/h) and time spent feeding (27.3 vs. 19.2 ± 1.3 min/h) during the peak period, compared with cows that were not restricted. Restricting temporal access in conjunction with overstocking resulted in the greatest increase in daily displacements (15.0 vs. 3.8 ± 1.4 displacements/d); the majority of these occurred during the peak period. Adequate space and time to access feed is essential to minimize feed bunk competition in indoor group-housing systems.Land and Food Systems, Faculty ofGraduat