Dairy cow trade-off preference for 2 different lying qualities: Lying surface and lying space

Lying down is an important behavior for cows, contributing to their health and welfare. With dairy cows being housed for increasingly longer periods, if not year-round, it is important to ensure that dairy cow lying comfort is not compromised when they are housed. The aim of this study was to assess cow preference for 2 different qualities of lying area that appear to be important to cows-surface type and an open lying space-to better understand how to optimize lying comfort for cows when housed. Twenty-four Holstein dairy cows were used during the study, which took place in Scotland from July to November 2018. The study consisted of 6 experimental periods, each lasting a total of 21 d. Cows were tested 4 at a time and individually housed in their own test pen. Each pen had 3 lying surfaces: sand, mattress, and straw (2.4 m × 2.4 m each) with a freestall in the middle of each, which could be removed. Cows were given access to one surface at a time (training period) with a freestall for 2 d, and then given a choice of all 3 surfaces for 2 d. When given the choice with freestalls in position, cows spent, on average, the largest amount of their lying time on straw (46.6 ± 7.8%) followed by mattress (44.3 ± 12.4%). Freestalls were then removed and the training and choice phase was repeated on the following day, with cows, on average, spending the most time lying on straw (64.4 ± 7.2%). Finally, a freestall was refitted onto each cow's most preferred surface and the cows were given a choice between lying on their most preferred surface with a freestall (P1 + freestall) or on their second or third preferred surface without a freestall (P2 + open and P3 + open, respectively) for 3 d. During this final trade-off stage, of the 19 cows for which data were available, 14 cows chose to give up the opportunity to lie down on their most preferred surface to have more space on P2 + open and P3 + open, 3 cows chose to lie down on P1 + freestall, and 2 cows made no clear choice. Overall, cows spent the largest amount of their total lying time on their second most preferred surface as an open lying space (65.7 ± 6.9%) compared with their preferred surface with a freestall (20.5 ± 5.9%) and their third preferred surface as an open lying space (13.8 ± 3.7%). The results indicate that when lying down, these dairy cows value an open lying space more than the lying surface.