Ingestive behavior of Angus yearling steers in natural grassland subjected to fertilization and over sown of temperate species

Abstract

The objective was to evaluate the ingestive behavior of Angus yearling steers grazing natural grasslands of Southern Brazil, submitted or not to the application of fertilizers: NG= natural grassland; FNG= fertilized natural grassland, and FONG= fertilized natural grassland improved with the over sown of temperate forage species. Three Angus yearling steers and a variable number of put-and-take animals were used per experimental unit, to maintain a forage allowance of 13 kg of dry matter/100 kg of body weight. Ingestive behavior of tester animals was visually assessed in four seasons of the year through instantaneous records of activity every ten minutes during the daytime period. There was no effect of pasture treatments on ingestive behavior. An interaction between seasons and periods of the day was observed for daily grazing and rumination time (P <0.05). The grazing activities were clustered at the beginning and the end of the day in summer, autumn and winter, while in spring it was similar in the 1 st three quarters of the day, with higher activity in the period close to sunset. The animals spent more time grazing in the spring despite the better quality of forage in this season. Regardless of the season, longer residence and grazing time were found in water foci areas. We conclude that grazing time on natural pastures is influenced by forage mass and forage allowance, and bite rate is influenced by the chemical composition of the sward.