Implications for winter grazing managements and dead material on the performance of young cattle in spring

Data from an experiment investigating the impacts of winter dead material content and winter grazing intensity on spring pasture productivity and botanical composition, were used to estimate the impacts of agronomic outcomes on the potential production of young cattle during spring. The experiment was replicated at two sites (heavy and light soil types of moderate to high fertility in a cool temperate climate). Q-Graze software was used to determine liveweight gain (LWG) and grazing days of Angus steers (300 kg starting liveweight) grazing the pastures during spring at a stocking density of 20 steers/ha (an overall stocking rate of approximately 4 steers/ha). The reduction in dead material by intensive winter grazing strategies increased the estimated quality of pasture available by 0.5 MJ ME/kg DM (P=0.002). Spring pasture production was higher when winter dead material content was low or medium compared with a high winter dead material content, leading to a reduction in LWG of 0.38 kg LW/day (P<0.05). The imposition of intensive winter grazing on pastures with medium proportions of dead material increased steer LWG in spring from 0.39 to 0.64 kg/day, and from 0.22 to 0.33 kg/day when high dead material content was present in winter (P<0.05). Total LWG/ha for spring was increased by using intensive grazing management to remove winter dead material, and with medium or high dead material content compared with using a lax grazing approach (P<0.05) in winter.