Diurnal ingestive behavior of Nellore steers receiving increasinglevels from supplement in pasture of Brachiaria brizantha

The objective of this experiment was to evaluate the diurnal ingetive behavior Nellores steers with increasing levels of energy and protein supplemention by raising in pasture of Brachiaria brizantha. The on-farm trial was developed at Boa Vista Farm in conjunction with Bahia State University, southwestern Bahia, Brazil, where forty 26-month-old Nellore steers with the initial weight of 371.0 ± 14.9 kg were previously accommodated to the experimental conditions for 14 days; they were randomly allotted in the following treatments: T 00 = mineral salt, T 03 = 0.3%, T 06 = 0.6%, and T 09 = 0.9% of energy and protein supplementation for 84 days. The animals were visually observed at 10-minute intervals for two periods of 12 hours from 6:00 am to 6:00 pm. Time for ruminating (P<0.06) had cubic effects; time for grazing (P<0.00001) and idling (P<0.00006) had quadratic effects while time for feeding had increasing linear effects (P<0.00001). The total of feed dry matter intake either in kg/animal/day or percentage (%) of the live body weight were not affected by increasing the levels of energy and protein (P>0.15). However, the total of dry forage intake and the fiber contents evaluated in neutral and acid detergent were linearly reduced (P<0.0002). Furthermore, the total time of chewing the number of bolus, and the ruminating time per bolus had cubic effects (P<0.0001); the chewing number per bolus was linearly reduced (P<0.000001); the number of grazing events (P<0.15) and the time of feeding was linearly increased (P<0.000001) although each grazing event had its average time linearly reduced (P<0.000001); the number of ruminating (P<0.02), idling events (P<0.000001), and time for each ruminating event (P<0.0002) had quadratic effects. Finally, the number of events at trough had cubic effects (P<0.000001) but the time of each idling event was not modified by the treatments (P>0.15). Therefore, it is necessary to pay special attention to the diet composition for raising beef-cattle and to the amount of feed in conjunction with both composition and ratio of pasture to concentrate because some diurnal behavior which have affected on the ingesting performan-ce of Nellore steers.

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