Ingestive diurnal behaviour of grazing beef cattle

Three experiments were conducted with the objective of evaluating the effects of supplementation (concentrate or mineral supplementation), supplementation strategy (continuous or strategic supplementation) and gender class on the ingestive and diurnal behaviour of grazing beef cattle. To evaluate the effect of the supplementation (Experiment 1) and the gender class (Experiment 3) on their diurnal behaviour, behaviour visualisations were performed by two people at observation stations outside the picket area with the aid of binoculars. The animal behaviour was classified as: supplement intake, grazing, water intake, standing ruminating, standing idle, lying ruminating, lying idle and walking. To evaluate the effect of the supplementation strategy on the ingestive behaviour of the supplement (Experiment 2), refusals of the supplement were weighed for six consecutive days at different times (20, 40, 60, 90, 120, 180, 240, 480 and 1,440 minutes) after the concentrate was supplied. The intake of concentrate per animal, at each observation time, was calculated by subtracting the weight of the scraps at that time from the total weight of the batch of supplement provided on the day, and dividing the result by the number of animals in each batch. Finally, a logistic model was adjusted for each treatment. A 10% significance level was adopted for all statistical procedures. Concentrate supplementation reduced the time that the animals spent grazing. The continuous supplementation strategy affected the uniformity of the supplement intake speed, without affecting the average speed or the total supplement intake. The gender class of the animals also influenced their diurnal behaviour, castrated males spent more time lying, compared to females. The specificities of cattle behaviour should be considered when delineating the supplementation of grazing cattle, since the type of supplement, previous supplementation and gender class interfere with their behaviour.