Yeast-fermented cassava chip protein (YEFECAP) concentrate for lactating dairy cows fed on urea–lime treated rice straw

The objective of this study was to study the effect of YEFECAP (yeast-fermented cassava chip) in replacing soybean meal (SBM) in concentrate mixtures. Four, early lactating (30 ± 13 day-in-milk) Holstein Friesian crossbred cows (50 × 50; HF × Native Thai cattle) were randomly assigned according to a 4 × 4 Latin square design to receive 4 dietary treatments (4 replacement levels of SBM by YEFECAP at 0, 33, 67 and 100% CP in concentrates). Cows were offered concentrate mixtures according to concentrate:milk ratio at 1:2 Urea (2%)–lime (2%) treated rice straw was a roughage source and fed ad libitum. Measurements of feed intake and collection of feeds, feed refusals, feces, rumen fluid, and blood samples were taken. As a result of this experiment, it was found that, pH values in the rumen were linearly (P < 0.01) increased when increasing replacement levels of SBM by YEFECAP while ruminal NH3–N concentrations were not significantly different among treatments (P > 0.05). BUN and MUN were linearly decreased (P < 0.01) when increasing YEFECAP level. Total VFA and propionic acid (C3) were linearly increased (P < 0.05) when increasing YEFECAP level and were highest at 100% of replacement, while butyric acid (C4) and acetic acid (C2) were not significantly different among treatments (P > 0.05), hence, proportion of C2/C3 were linearly decreased. Population of bacteria and fungi were linearly increased (P < 0.01), especially the population of total viable bacteria, cellulolytic bacteria, amylolytic bacteria and proteolytic bacteria. Dry matter intake and organic matter digestibilities were linearly increased (P < 0.05) by YEFECAP levels. Moreover, increasing YEFECAP level was closely associated with linearly increased (P < 0.01) in milk yield, milk fat and milk protein. Based on this experiment, it could be concluded that YEFECAP can fully replace SBM in concentrate mixtures for milking dairy cows on enhancing rumen fermentation, dry matter intake, nutrient digestibility, milk yield and compositions.