Effect of fiber levels and protein sources on the eating behavior of crossbred Holstein-Zebu heifers

The objective of this experiment was to evaluate the effects of fiber levels, protein sources and feeding time on the eating behavior of crossbred Holstein-Zebu heifers. The diets with low (38.7% NDF) or high (57.2% NDF) fiber were based on sugar-cane plus elephant grass silage. The protein sources were soybean meal for high (65%) and blood meal pills corn gluten meal far low (32.2%) ruminal degradability. Sixteen Holstein-Zebu crossbred heifers, averaging 14 months of age and 220kg of LW were allotted to a completely randomized experimental design in a 2x2x2 factorial arrangement (fiber level, protein sources and feeding time), with two replicates. The eating behavior of the heifers was determined by visual observation at 5 minutes interval during 24 hours once a month during the experimental period to determine the rime expend with eating, rumination and idling activity. The heifers on high NDF diets expend more time (min/day) eating, ruminating and idling than heifers on low NDF diets. The protein sources did not influence the time spent with eating, rumination and idling. The feeding time showed difference only for the time expend eating and the heifers fed in the morning expended more time eating. The NDF levels of the diets affected the eating behavior of the heifers.