Stocking density at feeders and drinkers and temporal feed restriction affects dairy cows' drinking behavior.

Water is an essential resource for dairy cows, and its consumption is closely linked to feed intake. Social competition can lead to changes in drinking behavior, especially for subordinate cows. We studied how changes in stocking density at the feeder (1 or 2 cows per feeder), and drinker (6 or 12 cows per drinker) and a temporal feed restriction (14- or 24-h access) affects drinking in 4 groups of 6 cows each, following a Latin square design. We recorded drinking behavior within each group of 6 focal cows, and 2 were identified as most dominant, 2 as most subordinate, and the 2 others as intermediate, based on success in agonistic interactions at the drinker. Cows drank less water when feed availability was restricted (on average 5.3 ± 3.4 [SE] L/d less; 4.5% average difference). Subordinate cows also spent less time drinking when overstocked (9.3 ± 6.7 min/d less; 24.3% difference). During treatments with more competition, cows were more likely to be observed drinking in the hours after the peak in drinking observed for the control treatment. A high level of competition among group-housed animals is considered a welfare problem and can lead to injuries and reduced production. Our findings provide evidence that feed restriction and higher stocking density of cows at the drinker and feeders changes the drinking behavior of cows, with subordinate animals experiencing more pronounced effects.