CONSEQUENCES OF REDUCTION OF NUMBER OF INDIVIDUAL FEEDERS ON FEEDING-BEHAVIOR AND STRESS LEVEL OF FEEDLOT STEERS

Thirty-six Hereford steers with an average weight of 230+/-23 kg, were randomly assigned to one of three groups of 12 animals to determine the consequence of decreasing feeder space on feed consumption, weight gain and stress. The animals were studied over a 28-day trial period. In Group A, each animal had access to an individual electronically controlled Calan Broadbent(R) feeder. Groups B and C had access to three and four feeders, respectively. During the trial steers were fed grass legume silage ad libitum with fresh silage added four times daily. Twenty-four hour feed consumption patterns and feed quantity were recorded for each individual steer through time lapse video monitoring of feed disappearance. Blood samples drawn on Days 0, 14 and 28 were analysed for cortisol and differential leucocyte counts. The animals were weighed on these sampling days at 09:00 h. Group A had the longest mean eating time per meal and the lowest number of eating bouts (P < 0.05). Group B had the lowest mean eating time (P < 0.05) but intake of Group B was not different from that of Group A (P > 0.05). Animals in Group B compensated for their shorter times spent at the feeder by increasing their rate of intake compared with those of Groups A and C (P < 0.05). The Spearman rank feeding order correlations for time at the feeder, number of feeding bouts and intake were positive for all groups, indicating that some animals consistently ate the most often and had the greatest intake. Groups A and B both had high Spearman rank feeding order correlations for mean meal length, total time at the feeder and number of feeding bouts (P < 0.05). These high correlations could indicate that subordinate animals were probably not disadvantaged by being fed in group feeding situation compared with animals fed individually. Neutrophil:lymphocyte ratios did not differ between groups on any sample day (P > 0.05). There were no significant differences in weight gains and cortisol plasma concentrations among experimental groups or time of sampling (P > 0.05). Reduction in number of individual feeders by two-thirds and three-quarters did not influence weight gains and it had no significant effect on stress levels. The results suggest that some degree of competition is desirable in the group feeding situation.