The effect of levamisole treatment every 3-4 weeks, cobalt therapy, or both, on the performance of yearling cattle grazing together on known cobalt-deficient pastures on a siliceous sandy soil in south-eastern Queensland was studied between August 1978 and October 1979. In the first stage of the observations, from August to March, the responses (Pc0.05) in liveweight gain compared with the controls (C) were 18, 54 and 75 kg for levamisole (L), cobalt bullets (B), and both (LB) respectively. Thus the responses were additive with no interaction. Deaths were recorded in the control and levamisole only groups in March. Steers in the levarnisole only group were treated with cobalt in March (L + B). Liveweight gains between March and October were 9, 71,47 and 41 kg for C, L + B, B and LB groups, respectively (L + B > B, LB > C, P< 0.05). Cobalt therapy increased faecal worm egg counts in undrenched groups between November and April (P<0.05). At 30 weeks after the start of the study many animals in groups C, L and B were anaemic. Cobalt concentrations in green panic ranged from 0.015 to 0.029 �g/g dry matter and in Siratro from 0.036 to 0.048 �g/g dry matter.
Weight gain of free-ranging beef cattle grazing in the boreal forest of south-eastern Norway
