Dairy cow preference for access to an outdoor pack in summer and winter

The aim of our study was to test the preference of freestall-housed dairy cows to access an outdoor deep-bedded open pack (versus remaining inside the freestall barn) in the summer and winter. A secondary aim was to investigate how preference for outdoor access influenced feeding, lying, and stall perching behavior. Eight groups of pregnant, lactating cows were tested in the summer and 9 groups in the winter. During both experiments, groups were allowed to stabilize for 5 d, followed by 2 d of baseline observations (baseline phase). Habituation to the outdoor pack took place for the next 2 d. Cows were then provided free access to the outdoor pack continuously for 5 d (choice phase). During the choice phase, in addition to feeding and perching behavior (recorded while cows were inside the barn), cow location (i.e., in the freestall pen or on the outdoor pack) was also noted. We used HOBO data loggers (Onset Computer Corp., Bourne, MA) to automatically record lying behavior during baseline and choice phases. Cows spent (mean ± standard error; minimum to maximum in parentheses) 25.3 ± 4.3% (8.0 to 44.5%) of their time outside in the summer and 1.8 ± 0.6% (0.1 to 4.1%) in the winter. In the summer, cows spent more time on the outdoor pack during night (50.0 ± 8.4% between 2000 and 0600 h) than during the day (3.3 ± 1.3% between 0600 and 2000 h). In the winter, we found no effect of time of day on time spent outside (day = 1.7 ± 0.7%; night = 2.1 ± 1.0%). Precipitation decreased the time cows spent outside during summer nights. During winter days, precipitation and increasing wind speeds decreased the time cows spent outside. In the summer, time spent feeding was higher during the baseline phase (18.7 ± 0.3%) than during the choice phase (17.4 ± 0.3%). During the winter, no difference in feeding time was found between the 2 phases (baseline = 18.7 ± 0.3%; choice = 18.4 ± 0.3%). During the summer, cows spent more time perching during the baseline phase (6.5 ± 0.5%) than during the choice phase (3.6 ± 0.5%) and this tended to be true during the winter (baseline = 5.5 ± 0.7%; choice = 4.5 ± 0.7%). Daily lying time did not differ between the baseline and choice phases in either the summer (baseline = 59.6 ± 0.9%; choice = 57.7 ± 0.9%) or winter (baseline = 63.0 ± 1.2%; choice = 62.6 ± 1.2%). When on the outdoor pack, cows spent 53.7% (±5.6) of the time lying during the summer and 4.7% (±2.5) during the winter. In conclusion, during the summer, cows displayed a partial preference to be outside on a deep-bedded open pack when given the opportunity, especially during the night, but in the winter, cows spent little time on the outdoor pack.