Pasture and sheep performance on tanzânia pastures submitted to defoliation intensities under continuos stocking

Abstract

In Brazil, the sheep production systems are related to pasture exploration. There is an increasing interest in utilization of tropical grasses as forage and the present study aimed to evaluate the responses of Panicum maximum cv Tanzânia to graze and evaluate the performance of growing sheep submitted to exclusive grazing. The pastures were kept under two defoliation intensities (treatments), corresponding to 25 and 45 cm height per animal under continuous stocking and variable stocking rate from January to April of 2001 and from February to May of 2002. The treatments were allocated on randomly under a whole randomized block design with split plot on experimental time (evaluated period) with four replications. Each experimental unit (450 m2) was grazed by two tracer lambs for animal responses estimation. Evaluated parameters were: total dry mass availability, total green dry mass, green leaf dry mass, leaf and stem percentile, dead material in swards, sward bulk density, herbage allowance, estimated live weight gain per animal and per area were estimated, carrying capacity and animal stocking. The sward structure and its morphological composition weren’t affected by the grazing height. The herbage allowance was higher in pastures managed to 45 cm height, being related to animal live weight gain and to area. The Tanzânia pastures allowed good animal performance and good carrying capacity.