Feeding behavior of crossbred steers fed diets containing babassu mesocarp meal and corn in kernels or ground

The objective of the present study was to evaluate the effect of the use of babassu mesocarp meal (BMM) and corn in different physical forms on the feeding behavior of crossbred young bulls of a dairy breed. Twenty-four crossbred (Nellore vs. Holstein) steers (307.35 kg) were fed four experimental diets containing two levels of inclusion of the babassu mesocarp meal (0 and 412.4 g/kg) and corn in two physical forms (kernels or ground) for 98 days. Data was collected on three days during the finishing phase, with observations every five minutes, for 24 hours. When the activities performed by the animals were evaluated as a function of the period of the day, the physical form of the corn showed interaction with the BMM inclusion level on the time spent feeding and on other activities. When the activities were evaluated over the day, the defecation frequency was affected and decreased as BMM was included. The feeding time was longer at the moments that followed feed supply, whereas the time used for other activities increased during the morning period, regardless of the diet utilized. Rumination and idle times were affected by the period of the day and remained high during the night and morning periods. There was increase in feeding time and dry matter rumination efficiencies and neutral detergent fiber as BMM was added to the diet. The number of rumination chews per bolus, however, decreased as BMB was included. Inclusion of babassu mesocarp meal increases the animal feeding time but the physical form of corn does not change its feeding behavior.

本研究旨在评估不同物理形态的巴巴苏中果皮粕（babassu mesocarp meal, BMM）与玉米对奶用品种杂交青年公牛采食行为的影响。试验选取24头内洛尔牛与荷斯坦牛的杂交阉牛，初始体重为307.35 kg，饲喂4种试验日粮，日粮设置2个巴巴苏中果皮粕添加水平（0与412.4 g/kg），并搭配2种物理形态的玉米（完整籽粒或粉碎状），试验周期共计98天。数据采集于育肥阶段的3天内，每5分钟进行1次观测，连续记录24小时。当按一日内的时段评估动物行为活动时，玉米的物理形态与巴巴苏中果皮粕添加水平对动物采食时长及其他活动时长存在交互效应。当按全天时段评估行为活动时，随着巴巴苏中果皮粕添加量提升，排粪频率降低且受到显著影响。采食时长在饲粮供给后的时段更长，而无论使用何种饲粮，上午时段的其他活动时长均有所增加。反刍与静息时长受时段影响显著，在夜间与上午时段维持较高水平。随着日粮中添加巴巴苏中果皮粕，动物的采食时长、干物质反刍效率以及中性洗涤纤维水平均有所提升。然而，每食团的反刍咀嚼次数随巴巴苏中果皮粕添加量增加而降低。添加巴巴苏中果皮粕可延长动物的采食时长，但玉米的物理形态不会改变其采食行为。