Grazing systems for winter cereals

To make an economic assessment of the role of grazing cereals in farming systems, it is necessary to estimate the impact of grazing on the yield of the crop and determine any benefits to livestock production. It is the second of these components that is the subject of this paper. Two grazing systems, each replicated three times, were compared in terms of pasture availability and the liveweight gain of 30 kg Merino x Dorper lambs. Lambs grazed either lucerne pasture (composed of lucerne ~ 50% with barley grass, annual ryegrass and capeweed) for 18 weeks from 13 June to 15 October 2007 (treatment L) or lucerne pasture for 6 weeks followed by wheat (cv. EGA Wedgetail) for 6 weeks and then returned to the lucerne for a further 6 weeks (treatment LW). Lucerne plots were divided into three sub plots, which allowed the establishment of a 2 week on – 4 week off rotational grazing system, and were grazed at a stocking rate of 12.5 lambs/ha. Average liveweight gain for the LW treatment (20.1 kg/head) was significantly greater than the L treatment (16.1 kg/head). This difference in liveweight was only apparent at the end of the period of grazing the wheat crop. For the period after the LW lambs were returned to lucerne pasture there was no significant difference in the rate of liveweight gain between the two treatments. These results are discussed with respect to the future of systems level research in grain and graze enterprises.