Effect of outdoor open pack space allowance on the behavior of freestall-housed dairy cows.

Providing dairy cows access to pasture is desirable, given their strong motivation for pasture access, but this practice is hindered by several practical constraints, including lack of available pasture. An alternative to pasture is an outdoor area that is bedded with a soft material such as sand or wood chips that requires less space than pasture, given the absence of soil or grass that can otherwise be damaged by cow traffic. However, little is known about space requirements for alternative outdoor areas. This study investigated how space allowance affected cow preference to be outdoors as well as cow behavior on an outdoor pack. A total of 3 groups of 24 pregnant, lactating, healthy Holstein cows were used. Each group was given 3 d for social dynamics to stabilize; during this time cows were kept indoors in a freestall pen. A habituation phase of 5 d followed, where animals were given free access to the outdoor pack with a space allowance of 16 m/cow. Cows were moved outside (if not already outdoors) at set times each day during the habituation phase (i.e., 5 times during the first 2 d and 2 times during the last 3 d). Cows were then given free access to the outdoor pack, but space allowance was changed every day. A total of 13 different space allowances were randomly applied, without replacement, ranging from 4 to 16 m/cow in 1-m increments. Using continuous video recordings, the location of the cows (i.e., in the freestall barn or on the outdoor pack) as well as displacements from a lying position on the outdoor pack were scored. Standing and lying behaviors were automatically measured using HOBO data loggers (Onset, Cape Cod, MA). Over the 24-h period, cows spent more time outside with increasing space allowance, but this result was driven almost entirely by the increased time spent outdoors during the nighttime hours. During the night, space allowance did not influence the number of displacements from lying on the outdoor pack or the proportion of time on the outdoor pack that cows spent lying down. Our results indicate that cows use an outdoor bedded pack mostly at night and that the time spent outside at night increases with increasing space allowance. Providing an outdoor bedded pack should be considered when designing dairy cattle housing systems.