RESUMO
The relationship between live body weight, milk yield and feed intake of dairy cows were measured in two group experiments. The first group with 30 grazing cows and the second group with 16 cows fed indoors on fresh pasture individually that harvested daily. Both experiments included Holstein cows which were chosen to be similar in yield of milk, age, parturition number, stage of location but widely different in live body weight. Feed intakes by the grazing cows calculated from estimated faecal outputs, measured using chromic oxide as the indigestible marker. The relationship between daily metabolizable energy intake, daily milk energy output, live body weight arid daily changes in live body weight were measured by multiple regression analysis. The results showed that live body weight had a significant effect on MEI [at a common milk energy output] and therefore on feed conversion efficiency and light cows have more feed conversion efficiency