The effect of grazing management on pasture and animal production late Autumn to Early-Spring period in a one year Bull Beef Grazing System.

The aim of this trial was to improve pasture growth rate and animal liveweight gains in the late autumn and early spring on a one year bull beef production system. The trial was conducted at the Tuapaka bull unit, Massey University, from 1 April to 30 September 1997. It compared three contrasting managements, operating on a total of 165 bulls stocked at 2.6 bull/ha. Treatment 1 followed a grazing plan based on the average pasture growth rate for the region, the animal requirements needed to achieve performance targets, and pasture mass targets (2700-2800 kg DM/ha and 1500-1600 kg DM/ha for late autumn and early spring, and 3000-3200 kg DM/ha and 1100-1200 kg DM/ha for winter for pre-grazing and post-grazing, respectively). Treatment 2 was managed according to the same pre-grazing and post-grazing targets. In this treatment the pasture targets were monitored daily, and bulls were shifted when the post-grazing targets were achieved. No supplement was used in Treatments 1 and 2. Treatment 3 followed traditional Tuapaka management, based on a 50 day rotation over the late autumn and winter, a 30 day rotation in August, and set stocking in September. Supplement was fed to this treatment as required in the winter. The overall liveweight gain (0.84 ± 0.02, 0.87 ± 0.02, 0.74 ± 0.01 kg LW/head/day for Treatments 1, 2, and 3 respectively) and final liveweight (354.7 ± 3.54, 359.8 ± 3.65, and 335.6 ± 3.27) were similar for Treatments 1 and 2 which were both significantly higher (P<0.001) than Treatment 3. Net herbage accumulation was significantly different (P<0.01) between Treatment 1 (6147 ± 369.3 kg DM/ha), Treatment 2 (7062 ± 319.9 kg DM/ha), and Treatment 3 (5277 ± 334.08 kg DM/ha). It was concluded that it is possible to improve both pasture production and bull beef performance when grazing is based on the management of prescribed sward conditions.