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The acute toxicity of zinc, cadmium and copper to A. compressa was assessed in single, paired and triad combinations. Copper was 1.6 times more toxic than cadmium and 4 times more toxic than zinc. When tested in combinations of paired metals, independent dissimilar and simple similar action models, both of which are non-interactive in their classification, were rejected. In one case, the expected mortalities were lower (antagonism) which suggested that paired metals acted interactively. For the combination of three metals, the mortalities were predictable by the simple similar action model (non- interactive). Except for the Zn-Cd combination, the toxic unit concept underestimated the expected mortalities in the test combinations.

The growth of lambs weaned at 4 weeks of age on to pure stands of lucerne was compared with that of lambs suckling their dams on similar lucerne and also with suckled lambs on ryegrass-white clover pastures. Growth rate of early-weaned lambs was severely checked immediately after weaning, when levels of sodium (0.060/0), fibre (16°m), and dry matter (13%) were low in lucerne. They also developed an apparent "pica" for soil after weaning, Three percent of early-weaned lambs died of "red gut". No lambs died while suckling, and none died when transferred to weedy lucerne at 11 weeks. Final live weight at drafting at 15 weeks was 28 ± 0.2 kg for the early-weaned group and 32 ± 0.3 kg for the suckled groups. 15