Three pastures, pangola–clover, setaria, and tropical grass–legume, were grazed for a 9-month period by 12 steers of initial live weight of 199 kg on each. For the first 5 months live-weight gains were, respectively, 1·2, 0·76 and 0·43 kg per day, mostly higher than could be expected for estimated dietary energy concentrations of 10·1, 8·9 and 8·7 MJ of metabolizable energy (ME) per kg of dry matter. The high live-weight gains were not explained satisfactorily by dry-matter intakes as measured from faeces voided and dietary digestible dry matter, but were possible if published values for the requirements of ME for growth and fattening were too high. Cell wall, in vitro digested cell wall and nitrogen in separated leaf and stem fractions were useful indices for evaluating pasture for grazing cattle, but they did not predict live-weight gain.

On 13 pastures grazed by beef cattle live-weight gain (range, 0·34–1·12 kg/head/day) was significantly correlated with non-green grass content of pasture. In turn, non-green grass in pasture was not significantly correlated with non-green grass in oesophageal extrusa. Live-weight gain was largely explained (adjusted R2 = 0·91) by non-green grass content of pasture, cell-wall content of green-grass leaf and pasture dry matter on offer in a quadratic model. The quadratic form was best understood in terms of pasture growth with which non-green grass content of pasture was significantly and negatively correlated.

Growing beef cattle grazed six pasture types (all-grass or grass-legume mixtures) for 4 months on each. Live weight (mean of ten animals) and dietary energy concentration were measured at 2- or 3-weekly intervals. Values for feed intake estimated by back-calculating from feeding standards were on average 2·5% higher (range, 10% less to 12 % higher) than intake values estimated directly from dietary energy concentration and live weight. In contrast to this level of agreement of means, differences between methods within pastures were so large as to suggest the presence of overriding effects on predictors of voluntary intake. It was concluded that until these overriding effects are explained, there are no means of validating measured intakes in grazing cattle, or of accurately predicting the amount of beef produced from pasture.

Live-weight gain of beef cattle grazing all-grass or grass-clover pastures, details of which have been reported previously, was significantly (P < 0·01) correlated with pasture growth rate, but not with pasture dry matter on offer (either total or green), or with dietary-energy concentration. From ideas generated from the relationship between live-weight gain and pasture growth rate, and using intake values measured from the number and size of prehension bites, it is shown how high live-weight gain for measured dietary-energy concentration could be explained by differential contribution to digestibility and voluntary intake from pasture new growth.