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Competition in the milk-feeding stage affects post-weaning feeding behavior of pair-housed dairy calves
This study investigated the effect of competition during the milk-feeding stage on post-weaning feeding behavior and response to a competitive feeding challenge. Twenty Holstein bull calves were pair-housed and provided milk replacer (MR) and grain concentrate ad libitum via either: 1) 1 teat and feed bucket/pen (competitive feeding: CF) or 2) 2 teats and feed buckets/pen (non-competitive feeding: NCF). Calves were weaned during wk 7 of life by incrementally diluting the MR. Post-weaning, all pens were managed similarly and offered a complete pelleted diet ad libitum via 2 feed buckets/pen (non-competitive feeding) in Period 1 (wks 8 and 9) and Period 3 (wks 12 and 13) and 1 feed bucket/pen (competitive feeding) in Period 2 (wks 10 and 11). Post-weaning feeding times and competitive interactions were recorded 2 d/wk from video. Meal criteria were used to calculate daily meal frequency, meal time, and synchronized meal time (the percentage of meal time when calves within the pen were engaged in simultaneous meals). Data were summarized by week and analyzed in a repeated measures general liner mixed model. Post-weaning, calves raised in CF pens displaced one another more frequently (6.6 vs. 1.5 displacements/d, SE = 1.9, P = 0.02) and had fewer overlapping meals than calves raised in NCF pens (34.5 vs. 40.7 % of meals, respectively). In Period 1 (non-competitive feeding), calves in previously CF pens had (P = 0.03) more frequent meals than calves in previously NCF pens (10.8 vs. 9.8 meals/d, respectively) and tended to have (P = 0.09) greater rates of intake (44.3 vs. 38.9 g/min). Likewise in Period 3 (2 buckets/pen), previously CF pens had (P < 0.04) more frequent meals (11.3 vs. 9.9 meals/d) and greater rates of intake (87.8 vs. 72.0 g/min). In Period 2 (competitive feeding with 1 bucket/pen), meal frequency and rate of intake were subject to treatment × week interactions (P < 0.004), increasing to a greater extent in previously NCF pens compared to previously CF pens. Feeding behavior across treatments was affected by the competitive feeding challenge in Period 2 (P < 0.04): feeding time decreased by 18 %, meal synchrony decreased by 16 %, and displacement frequency increased 1.7 ×. These results indicate that behavioral responses to pre-weaning competition, such as competitive displacements, degree of feeding synchrony, and rate of intake, may persist once developed.
Keywords: dairy calf, competition, feeding behavior