Evaluating effects of providing hay on behavioral development and performance of group-housed dairy calves

摘要

Providing access to forage has been shown to influencefeeding behavior and non-nutritive oral behaviorin individually housed calves, and these effects may beenhanced or altered in calves reared in social housing.We evaluated the effect of hay provision on the behavioraldevelopment and performance of group-houseddairy calves. Holstein calves (n = 32) were grouphoused(4 calves per group) at 17 ± 3 (mean ± SD) dof age. All calves were provided milk replacer (8 L/d)via an automated milk feeder and pelleted starter andwater ad libitum. Pens were randomly assigned to receiveeither chopped coastal Bermuda grass in bucketsadjacent to the starter trough (starter and hay, STH; n= 4 pens), or no additional feed (starter only, ST; n =4 pens). Calves were weaned through a 10-d stepdownprogram beginning at 46 d of age. Intake of solid feedand hay were recorded daily, and body weights weremeasured weekly. The behavior of 2 focal calves perpen was recorded continuously from video for 12 h on2 consecutive days during each of wk 4, 6, and 7 of life,to measure solid feed intake time, grooming, and pendirectedsucking. Hay provision influenced total feed intake,with calves provided hay having greater total solidfeed intake in the week before weaning (0.79 vs. 0.55kg/d, STH vs. ST, respectively; SE = 0.19). Averagedaily gain (ADG) was similar during the pre-weaningperiod but tended to be greater for STH calves duringweaning. Calves in pens provided hay also had fewerunrewarded visits to the milk feeder during weaning(12.5 vs. 21.1 visits per 12 h, STH vs. ST, respectively;SE = 3.59) and performed less pen-directed sucking(9.11 vs. 19.3 min per 12 h, STH vs. ST, respectively;SE = 2.86). Self-grooming time and bout characteristicsevolved differently between treatments over time, withpens of calves provided hay having a greater increase infrequency and duration of self-grooming bouts duringweaning. Overall, we found that providing hay to preweanedcalves resulted in behavioral and performancebenefits, including greater total feed intake and reductionsin pen-directed sucking, suggesting that access tohay may improve calf welfare.