Responses to grain : sunflower meal supplements by weaned calves grazing mature pasture or eating hay in pens

摘要

In southern Australia, winter-born calves may not be at marketable weights until 18 months of age and can thus compete with their dams and the next crop of calves for the pasture resource. We investigated supplementary feeding options to improve calf liveweight gains and overcome this problem. Weaned beef calves confined to feedlots for 70 days were fed different ratios (1 : 1 up to 1 : 4) of sunflower meal to oat grain (Experiment 1) or barley grain (Experiment 2) at levels of 3–6 kg air-dry/day, plus either oaten hay (Expt. 1) or pasture hay (Expt. 2) fed ad libitum. Liveweight gains at 3 kg supplement/day were ~1.2 kg/day at all ratios and were slightly higher at the higher feeding levels. The intake of hay varied inversely with the amount of supplement fed and substitution rates were 0.49 with oaten hay and 0.47 with pasture hay. Total DM intakes did not decline in Experiment 1 as supplement intake increased and increased in Experiment 2 with increasing supplement intake.