Trade-offs between feeding and social companionship in cattle: Intra-animal consistency over short and extended periods

摘要

The conflict between sociability and foraging motivation in animals is considered to be of potential value for use in the management of grassland systems to improve grazing pattern of livestock over grasslands. However, individual differences in behaviors relating to this conflict have not been fully explored. Three experiments with two test repeats 1-3 days apart were conducted using 8-16 Japanese Black cows at intervals of approximately 3 weeks between Experiments 1 and 2 and 1 year between Experiments 2 and 3. Individual cows were tested in a grassed arena (85 m x 30 m in Experiments 1 and 2, 130 m x 18 m in Experiment 3) with an adjoining group pen holding the peers. Plastic washtubs (16 in Experiments 1 and 2,25 in Experiment 3) containing 150 g grain-based concentrate were placed at 5 m increments on the centerline of the arena to entice test cows away from the group. Behavior of test cows were recorded for 30 min as: maximum (D-max) and mean (D-mean) distance from the group, number of total (N-total) and different (N-diff) tub visits, and proportion of time eating concentrate (P-eatconc) and grazing sward (P-graze). Cows showed consistency in D-max, D-mean, N-total and N-diff over the short periods of 1-3 days (repeatability within experiments = 0.41-0.80) and approximately 3 weeks (Pearson r between Experiments 1 and 2 = 0.81-0.91, P < 0.05). Cows were further consistent in D-max, N-total and N-diff over the extended period of 1 year (Pearson r between Experiments 2 and 3 and between Experiments 1 and 3 = 0.68-0.93, P < 0.05). By contrast, P-eatconc and P-graze showed poorer consistency within cows, giving low repeatability estimates (0.29-0.34) in Experiment 2 and low Pearson r between Experiments 2 and 3 (0.30-0.31,P > 0.05). It was concluded that D-max, N-total and N-diff provide a reliable measure of the propensity for individual cows to trade sociability for feeding when the test is repeated over both short and extended periods. A test arena longer than 130 m would be necessary for fully discriminating individual behavioral traits of cattle. (c) 2013 Elsevier B.V. All rights reserved.