Group sizes effects on growth performance and behavioural characteristics in Korean native calves

ABSTRACT Effects of group size on performance and behavioural characteristics in Hanwoo calves including heifers (BW？=？140.7？±？3.8？kg, 8？±？0.5 month) and steers (BW？=？167.2？±？3.4？kg, 8？±？0.6 month) were evaluated. Fifty-four calves (27 steers and 27 heifers) were assigned to three group sizes, with either 4 (G4), 3 (G3) or 2 (G2) animals per pen, with 3 pen replicates. Data obtained were analysed using the MIXED procedure of SAS. BW was measured bimonthly until the end of the study, and behavioural observations were performed weekly. In heifers, BW showed no differences (P？>？.05) at neither 8 nor 10 months, however, it was higher (P？<？.05) in the G4 than the G2 in both 12 and 14 months of age, respectively. In steers, there were no significant differences (P？>？.05) among the groups in BW, average daily gain, and feed conversion ratio at 8 and 10 months. In heifers, drinking, self-grooming, pairwise grooming were higher in the G4 and G3 than the G2 group (P？<？.05). The effect of time on performance and behavioural characteristics was highly significant (P？<？.01). Collectively, the number of 4 calves per pen (32？m2) can be suggested to improve growth performance in Hanwoo calves