RESUMO
Dairy cow lying behavior is useful in determining the cow's level of welfare, as well as in determining how her environment may affect her comfort and ease of movement. In tiestall systems, cows usually remain in a stall for the duration of their lactation. The dry period offers a unique opportunity to provide alternative housing to the cow with minimal effects on farm housing and management. Our objective was to determine whether housing tiestall cows in deep-bedded pens over an 8-wk dry period altered lying time, lying and rising ability, or lying postures. At dry-off, 20 cows, paired by parity and calving date, were randomly assigned to a deep-bedded loose pen (LP) or a tiestall (TS). Leg-mounted pedometers measured lying time. Rising and lying ability were measured using 6 events of rising and lying from 24-h video recordings taken once a week per cow. Sequenced images (1/min) from the 24-h recordings were used to document lying postures and locations for each cow. Data were analyzed for the early (first week of dry-off), mid, and late (week before calving) terms of the dry period. Lying time did not differ between LP and TS but was numerically higher for LP than TS cows (14.4 vs. 13.0 h/d, respectively). Contact with stall or pen confines when lying down was 5 times higher in TS than LP. The increased contact, coupled with a higher occurrence of hindquarter shifting in the late term, led to higher overall abnormal lying behaviors in TS. Contact with the stall upon rising increased in the late term for TS cows. Cows housed in loose pens also exhibited greater variation in hind-leg postures, keeping legs tucked 20% less often in favor of alternative postures. Stall hardware (e.g., tie rail, dividers) may have affected the ease of transition between lying and standing, leading to higher levels of contact with the stall. Loose-pen cows are able to assume more postures than TS cows when provided more space, possibly allowing them to orient themselves in ways that provide greater comfort. Lying surface in the deep-bedded loose pen may ease the cow's lying-down and rising movements and lead to the higher lying time found with LP cows. Overall, aspects of the stall largely contributed to differences in lying behaviors, warranting further study into whether freestall systems would yield similar outcomes. Improving our concept of ease of movement related to lying and quality of rest in dairy cows, through evaluating lying behaviors in different housing systems, allows for better recommendations on viable alternative housing options.
