An evaluation of the production potential of six tropical grasses under grazing. 3. Responses to set stocking rates under continuous grazing

Abstract

The response of 3 setaria cultivars, the setaria variety splendida, kikuyu grass, and pangola grass to stocking rates of 4-6 steers/ha under continuous grazing was evaluated over a 3-year period. On a year-round basis, averaged over stocking rates, liveweight gain per ha ranged from 822 kg on Narok (164 kg/steer) to 568 kg on Kazungula (114 kg/steer). Narok produced the highest weight gains in summer and winter (142 and 23 kg/steer, respectively). The greatest winter weight loss was from steers grazing Nandi and Kazungula (both -15 kg/steer). Animal production in a year of above-average rainfall, in both summer and winter periods, was markedly reduced overall, even though the quantity of feed on offer was increased. The year x grass interaction was statistically significant in summer, but year x stocking rate and grass x stocking rate were not. Species response to stocking rate showed a linear relationship between stocking rate and liveweight gain per steer, declining with increasing stocking rate, except for Narok setaria where the reverse occurred over the range of 4-6 steers/ha. The results of this experiment support those previously published on these 6 grasses and demonstrate the species potential for good levels of animal production per ha and their ability to withstand high grazing pressures and to maintain weed-free pastures.