Yeast mixture of liquid beer and cassava pulp with rice straw for the growth of dairy heifers.

This study was conducted to determine the effects of mixtures of liquid brewer's yeast (LBY) and cassava pulp (CVP) with rice straw (RS) on feed intake, digestibility, rumen fermentation, and growth of dairy heifers. Sixteen Holstein crossbred heifers (13.8 ± 1.6 months old, 210 ± 23 kg body weight (BW)) were randomly allocated to four feeding treatments with four replications, which were 0:0:100 (RS), 0:70:30 (0%LBY), 20:50:30 (20%LBY), and 50:20:30 (50%LBY), respectively, for LBY/CVP/RS on a fresh matter basis. The heifers were offered conventional concentrate at 1.5% initial body weight daily and fed the treatment diets ad libitum. Average daily gain and feed intake were not significantly different among the treatments. The heifers fed 50%LBY had the highest crude protein (CP) intake and DM, OM, and CP digestibility (P < 0.05). The ruminal pH did not differ significantly among treatments, while NH3-N was the highest (P < 0.05) in 50%LBY. Total volatile fatty acid (VFA) concentrations and the molar proportion of each VFA were not significantly different among the treatments. Blood urea nitrogen concentrations of 50%LBY were the highest among the treatments (P < 0.05). The results indicated that 50%LBY improved CP digestibility.