The shortest ruminating time (RT, P = 0.0181) was recorded in the treatment of lowest sward height. Despite differences in pasture structure, grazing time (GT) and idling time were similar among treatments ( P = 0.4266 and P = 0.2939, respectively). In addition, the productive and qualitative characteristics of the pastures were assessed. 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. 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. The objective of this study was to evaluate the ingestive behavior of young lambs grazing three different heights of Capim Aruana ( Panicum maximum). The efficiency of grazing ruminant production systems is directly associated to the animals' ingestive behavior, and to structural characteristics of the pastures. 2Department of Wildland Resources, Utah State University, Logan, UT, United States.1Departamento de Zootecnia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Joseane Anjos da Silva 1, Cesar Henrique Espirito Candal Poli 1 *, Jalise Fabíola Tontini 1, Lívia Raymundo Irigoyen 1, Elisa Cristina Modesto 1 and Juan Jose Villalba 2