The efficiency of grazing ruminant production systems is directly associated to the animals' ingestive behavior, and to structural characteristics of the pastures. The objective of this study was to evaluate the ingestive behavior of young lambs grazing three different heights of Capim Aruana (Panicum maximum). The experiment was carried out in two consecutive years, in which 30 tester lambs (4–5 months old) were equally divided into three paddocks (treatments) corresponding to different average sward heights of Aruana grass: (1) Tall-75 cm; (2) Medium-50 cm; and (3) Short-25 cm in a randomized block design. Ingestive behavior assessments were carried out every 28 days through 10-min observations of the main activities of the animals (grazing, ruminating, idling) and biting rate, from sunrise to sunset. In addition, the productive and qualitative characteristics of the pastures were assessed. Despite differences in pasture structure, grazing time (GT) and idling time were similar among treatments (P = 0.4266 and P = 0.2939, respectively). The shortest ruminating time (RT, P = 0.0181) was recorded in the treatment of lowest sward height. Lambs grazing on this treatment also showed 23% more bites per minute (P= < 0.0001) than animals in the Tall and Medium treatments. A Decision Tree analysis was performed for GT, identifying in a hierarchical order that the initial weight of the animals and sward height explained 62% (R² = 0.621) of the variation, representing the variables with the greatest influence on GT. Initial body weight explained 48% of the model. Thus, our research shows that the different sward heights of Capim Aruana mainly alter the lamb's RT and biting rate, and that the animals' initial body weight is a key factor influencing GT, given that this variable makes lambs more susceptible to changes in sward height.

放牧反刍动物生产系统的效率与动物的摄食行为以及牧场的结构特征直接相关。这项研究的目的是评估放牧三个不同高度的卡皮姆·阿鲁阿纳（Capim Aruana）的幼小羔羊的摄食行为（最大恐慌）。该实验连续两年进行，将30只测试羔羊（4-5个月大）平均分为三个围场（处理），分别对应于Aruana草的平均草皮高度不同：（1）高75厘米；（2）中号50厘米; （3）在随机区组设计中缩短25厘米。通过从日出到日落的10分钟观察动物的主要活动（放牧，反刍，空转）和咬食率，每28天进行一次摄食行为评估。此外，还评估了牧场的生产和质量特征。尽管牧场结构有所不同，但不同处理之间的放牧时间（GT）和怠速时间相似（P = 0.4266和 P分别为0.2939）。反省时间最短（RT，P最低的草皮高度记录为0.018）。在这种治疗下放牧的羔羊每分钟咬伤也增加了23％（P= <0.0001），比高和中等处理中的动物高。对GT进行了决策树分析，以分层的顺序确定了动物的初始体重和草皮高度解释了62％（[R² = 0.621），代表对GT影响最大的变量。初始体重解释了该模型的48％。因此，我们的研究表明，Capim Aruana的不同草皮高度主要改变了羔羊的RT和咬合率，并且动物的初始体重是影响GT的关键因素，因为该变量使羔羊更容易受到草皮高度变化的影响。