Carcass mass gains of steers grazing star grass, with different stocking rates and levels of applied nitrogen.

Abstract

Carcass mass gains of steers grazing dryland Cynodon aethiopicus cv. No. 2 Star grass pastures during the growing season were determined for each of 16 treatments comprising four levels of nitrogen fertilisation in combination with four overlapping sets of stocking rates. The treatments were repeated over four growing seasons. Patterns of response of carcass mass gain per steer and per hectare were established for each season by means of quadratic multiple regression equations. Similar equations were fitted to the mean herbage yields over the season. These indicated that the amount of herbage on offer per steer was the major factor affecting animal gain. However, there was a marked difference in the pattern of response between the first and the latter three seasons. This is attributed mainly to the differences in mass and condition of the animals at the start of each season and pasture maturation.

Keywords: cynodon aethiopicus; grasses; grazing; henderson research station; herbage; herbage yield; nitrogen; pastures; salisbury district; star grass; stocking rate; stocking rates; yield; zimbabwe