Grazing spring variety cereal crops reduces supplementary feeding in mixed cropping and sheep farms

The grazing of cereal crops has become widely adopted and interest in this practice has spread to the lowerrainfall parts of the cereal-livestock zone where i t is hard to grow long-season varieties. A modellin g study was conducted to investigate how the use of feedbas e components in a mixed cropping and sheep farm might alter when grazing of immature spring variety wheat and barley crops is allowed. The simulation study used climate data from 1961-2010 from 15 locations across southern Australia (annual rainfall 319 to 572 mm/year); the grazing management policy placed livestock on the crops only when green pasture mass was below 800 kg/ha. On average, supplementary feeding requirement in the grazing wheat systems was reduced from 15.9% to 14.8% of the energy intake of the she ep. Wheat crops were grazed in 47% of years for far ms located in drier climates, while at higher rainfall locations the frequency of grazing wheat averaged 20% of years, which was largely due to pastures being avai lable for grazing earlier relative to wheat. There was a correspondingly greater decrease in supplementary f eeding at the lower rainfall locations. There was a slightly larger utilisation of barley crops than wh eat crops (1.9% compared with 1.5% of the total ann ual energy intake from crop grazing). The difference wa s due to a longer average length of grazing with ba rley crops (25 v 17 days), owing to barley reaching sufficient stan ding biomass for grazing on average one week earlier than wheat. This simulation study suggests that grazing spring cereals is likely to reduce the cost of supplementary feeding of livestock marginally, but may be of greater value in seasons with late pastur e establishment.