In each of three consecutive years (1987/88 to 1989/90), 108 weaner steers (average live mass = 192.5 and standard deviation = 1.9 kg) were divided into three groups of 36 steers and fed to achieve growth rates of 0, 0.3 and 0.6 kg/steer/day durÂ¬ing winter. During the subsequent summer, the steers from each wintering level were subdivided into six groups of six steers each, which grazed either Smuts finger grass (Digitaria eriantha spp eriantha) or Nile grass (Acroceras macrum) pastures, each at one of three stocking rates (6, 8 and 10 steers/ha). Rotational grazing was applied. On average, steers subjected to wintering levels of 0, 0.3 and 0.6 kg/day subsequently gained 47.1 Â± 1.7, 38.2 Â± 2.1 and 34.9 Â± 2.2 kg/steer on Smuts finger grass and 63.5 Â± 2.2, 55.7 Â± 2.3 and 42.8 Â± 2.7 kg/steer on Nile grass pasture over a 90-day grazing period. Steers subjected to stocking rates of 6, 8 and 10 steers/ha gained 45.1 Â± 2.0, 39.2 Â± 1.8 and 35.8 Â± 2.4 kg/steer on Smuts finger grass and 61.8 Â± 2.1, 58.7 Â± 2.2 and 41.6 Â± 2.8 kg/steer on Nile grass. Prediction equations for summer live mass gain and final live mass were calculated. For all treatments, steers had better live mass gains when grazing Nile grass than when grazing Smuts finger grass [54.0 Â± 1.5 and 40.0 Â± 1.2 kg (P ≤ 0.01), respectively]. It was not clear whether the higher summer growth-rate on both pastures in animals wintered at maintenance was due to compensatory growth or to relatively more grass/kg live weight being available to the lighter animals.
Performance of beef steers on Smuts finger grass and Nile grass pasture in northern Natal 1. Effect of overwintering level and s
Author: W.D. Gertenbach, P.W. van H. Henning and A.P. van Schalkwyk
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