Short communication: dominance in free-stall-housed dairy cattle is dependent upon resource.

The main objective was to assess the consistency in competitive success across 3 common resources available to dairy cows housed in free-stall barns. Specifically, we determined if those cows that displaced other cows most often at the feed bunk (high-ranking) had priority of access to free-stalls or a mechanical brush. Our secondary objective was to determine if the displacements at each resource were a function of usage of that resource. These objectives were tested using 6 groups of 12 lactating dairy cows housed in pens with 0.6 m of bunk space per cow, 1 free-stall per cow, and 1 mechanical brush per pen. Time-lapse video was used to quantify the time spent feeding, in the stalls, and using the mechanical brush. The incidence of displacements at the feed alley and lying area was measured for 3 d consecutively. Usage was lower for the brush, so displacements were monitored for 14 d consecutively. The individual measures of competitive success were not highly correlated between resources indicating a cow that frequently displaced other cows for access to one particular resource did not always do so when accessing the other resources. Competition at the feeder was responsible for 87.6 +/- 1.4% of displacements observed throughout the experiment, indicating that gaining access to feed was a high priority for cows. These results suggest that competitive success by dairy cows may vary according to each cow's motivation to access the resource.