Strategic placement of supplements improves the dispersion of sheep and utilization of dual-purpose crops

Context Grazing sheep on crops provides mixed crop and livestock farmers with the opportunity to utilize available feed during early winter when demand for feed typically exceeds supply from pastures. However, this practice is associated with the risk of uneven grazing of the crop, which can lead to an increased risk of yield penalty in overgrazed areas of the crop. Aim The aim of this study was to improve the uniformity of crop grazing by attracting sheep from over- to under-utilized areas of a wheat crop with strategically placed supplement feeding stations. Methods Two paddocks of wheat were grazed for 2 weeks and plots of high (H), medium (M) and low (L) grazing intensity were identified from the analysis of sheep dispersion based on GPS tracking of seven sheep in each paddock. Supplement feeding stations were then placed in half of the plots identified as low supplemented grazing intensity (LS). Sheep were then reintroduced, and the paddocks were grazed for another 2 weeks to determine whether the placement of supplement altered the grazing distribution and intensity away from the H and towards the LS relatively more than to the L areas. Crop biomass cuts and visual grazing-score measurements were taken throughout the experiment to evaluate grazing intensity and any associated yield losses. Key results There was a significant increase in the number of GPS points in the LS plots and a decrease in the H plots after the supplement was introduced. Furthermore, there was no significant difference in grazing intensity between treatment plots after the supplement stations were introduced, indicating that grazing distribution became more uniform after providing the supplement. However, the biomass and grazing score data did not confirm the GPS data, which may have been due to high variability in biomass within paddocks. Conclusions Strategic placement of supplement feeding stations (as attractants) altered sheep grazing distribution by attracting sheep from areas of high to low grazing intensity within a wheat crop. Implications Given that feeding mineral supplements is a recommended practice for sheep grazing vegetative cereal crops, placing mineral supplement stations in strategic locations should be a cost-effective method to disperse grazing pressure and improve the utilization of dual-purpose crops that are grazed at low stocking densities. However, this will depend on a reliable and cost-effective way to identify areas of low paddock utilization, such as the commercial use of GPS tracking.