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Effects of bedding frequency on lying behavior of weaned calves
Twenty-eight Holstein male calves (BW: 79±3.1 kg, age: 78±2.5 d) were used to study whether lying behavior of weaned calves would be modified by bedding frequency. All animals were fed the same pellet concentrate and chopped straw, and they were bedded with sawdust, and kept in individual hutches. At the beginning of the study, 15-kg of sawdust were added to each hutch, and during the first 3 d of the study 3 kg of sawdust were added to each hutch (this was considered time 0 and used as covariate in the statistical analyis). Afterwards, on day 4, 6 kg of sawdust were added to all hutches, and thereafter half of the animals were bedded every other day (2B), and the other half every 4 d (4B) with 6 kg of sawdust. The study finished on day 11 (3 d for the basal time plus 2 periods of 4 d each). Animals were weighed on days 1 and 11 of study, and concentrate intake was measured daily. Lying behavior was monitored by placing a data logger in the right hind leg to record movements at 1-min intervals, and bedding samples were obtained daily to determine the moisture content. Data were analyzed with a mixed-effects model with repeated measures considering lying time or concentrate intake of the basal time as a covariate, and calf and period as random effects. Linear correlations were determined between the moisture content of the bedding, lying time and concentrate intake. Moisture content of the bedding was greater (P<0.001) the third and forth day of each experimental period in 4B than in 2B calves (50 vs 31 ± 4.8 % of moisture, respectively). However, neither lying time (1,111 vs 1,105 ± 6.1 min for 2B and 4B, respectively) nor DM concentrate intake (2.72 vs 2.76 ± 0.084 kg/d for 2B and 4B, respectively) or BW differed between both treatments. A slightly negative relationship was observed between moisture content of the bedding and lying time (r = -0.23, P<0.001), and also a slightly negative correlation was found between lying time and DM concentrate intake (r =-0.26, P<0.001). In conclusion, sawdust bedding at 50% moisture did not change lying behavior, DM concentrate intake, and performance of weaned calves in a short-period study.
Keywords:
bedding, lying behavior, weaned calves