The present work was under taken with the aim to investigate the effect of mineral/vitamin  premix supplementation on milk yield and milk quality of dairy cows when reducing concentrate in the diets and evaluate economic efficiency of Setaria sphacelata and premix feeding to dairy cows, thereby suggesting an appropriate strategy to improve net benefit for dairy farmers. It was shown that feeding cows with grass, rice straw and mineral/vitamin premix supplementation while reducing concentrate to 0.25 kg/kg milk yield helped to maintain and improve milk yield over 3 months with the best milk yield of 12.4 kg/cow/day. Finally, farmers applying new feeding strategy could get up to 43% more profit compared with those who used the conventional method. This feeding strategy is thus recommended for dairy cows to other farmers in Soc Trang province.