Abstract: This experiment was conducted to investigate the effect of various protein sources
on digestibility, rumen fermentation, milk yield and milk composition in dairy cows. Four
Holstein Friesian native crossbred cows in early lactating were randomly assigned according
to a 4x4 Latin square design. The dietary treatments containing different protein sources in
concentrate diets were soybean meal (SBM), cassava hay (CH), Leucaena leucocephala
(LL) and yeast-fermented cassava chips (YEFECAP), with ad libitum intake of urea-treated
rice straw. Digestibility of DM, OM, NDF and ADF was not different among treatments
(P>0.05) while CP digestibility was highest (P