This work was developed at Federal University of Santa Maria, RS, Brazil and its objective was to evaluate the behavior of lactating Holstein cows on a pasture constituted by elephantgrass (Pennisetum purpureum Schum.) and black oat (Avena strigosa). Four evaluations were taken (characterizing the winter period) on 06/12, 07/17, 08/25 and 09/14 of 2002. Five cows between second and fifth lactation month were used for each evaluation. The data was recorded at a 10 min-interval by two observers, from 6pm until 6am and from 8am until 4pm. The time of elephantgrass grazing, oat grazing, total grazing (elephantgrass plus oat grazing), rumination and idle were the parameters observed. The highest intensity of grazing was registered after morning and evening milking, starting from sunrise or from evening. It was observed a decrease lately, during the day as well as during the night. Diurnal grazing time was longer than nocturnal. The cows preferred the oat grazing not only in the beginning but also at the end of utilization. The elephantgrass was grazed at all evaluations at the winter period. The smallest rumination and the largest idle times were observed on 2nd grazing due to the major participation of oat and minor of elephantgrass on roughage diet.
elephantgrass; ethology; mixed pastures; oat
