Post-weaning growth of cattle in northern New South Wales - 2. Growth pathways of steers

This paper describes the post-weaning growth of Bos taurus and Bos taurus x Bos indicus-derived steers grazing temperate perennial pasture in northern New South Wales. These cattle were either autumn weaners from spring-calvi ng herds in summer rainfall environments, or summer weaners from autumn-cal ving herds in winter rainfall environments. Autumn weaners were grown out o n 3 pasture systems: (i) pasture only (P1), (ii) pasture supplemented in la te winter-early spring with formulated pellets of high protein content (P2) , or (iii) pasture supplemented with a nitrogen-fertilised forage crop (P3) to provide different growth pathways towards entry to the finishing phase. Over the 3-year study, seasonal liveweight gain on P1 varied between -0.21 and 1.05 kg/head. day; liveweight gain was generally low (about 0.5 kg/hea d. day) in winter and high (about 0.8 kg/head. day) in spring. Bos taurus a utumn weaners achieved feedlot entry specifications for the domestic market (300 kg liveweight) in 6-8 weeks by the end of winter, and feedlot entry s pecifications for the export market (400 kg liveweight) in 17-27 weeks by t he end of summer. For B. taurus x B. indicus-derived autumn weaners, the pe riod to feedlot entry was 19 and 33 weeks for domestic and export feedlot e ntry specifications, respectively. Supplementary feeding generally increase d post-weaning growth in late winter-early spring and reduced the period to feedlot entry for export steers. Summer weaners were grown out on pasture in P1, P2 or P3 pasture systems, met domestic feedlot entry specifications on arrival, but did not reach export feedlot entry specifications before th e onset of winter imposed liveweight stasis. The most effective grow-out sy stem was based on Bos taurus autumn weaners with supplementary feeding in w inter-spring to overcome the limitations of the winter feed gap.