Feed utilization efficiency and ruminal metabolites in beef cattle fed with cassava pulp fermented yeast waste replacement soybean meal

The purpose of this study was to see how substituting cassava pulp fermented yeast waste (CSYW) for soybean meal (SBM) in a concentrate affected feed intake, digestibility, and rumen fermentation in Thai native beef cattle. In this study, four male Thai native beef cattle with an average age of 15.0 ± 25.0 months and body weights of 140 ± 5.0 kg were used. The experimental design was a 4 × 4 Latin squared design, with dietary treatments of CSYW replacing SBM at 0, 33, 67, and 100% in the concentrate mixture. It was discovered that the presence of CSYW had no negative impact on feed intake, nutritional intake, or apparent digestibility (p > 0.05). CSYW had no significant effects on ruminal pH or temperature (p > 0.05). When the amount of CSYW in the diet increased, the rumen ammonia–nitrogen concentration increased (p < 0.05). Blood urea nitrogen was not affected by CSYW (p > 0.05). The total bacterial population increased when the diet's CSYW amount was increased (p < 0.05). Feeding CSYW to beef cattle had no influence on total volatile fatty acid, acetic acid (C2), or butyric acid (C4) proportions (p > 0.05). The concentration of propionic acid (C3) and the C2:C3 ratio increased when the amount of CSYW in the diet was increased (p < 0.05). In conclusion, CSYW can completely replace SBM in a concentrate diet for beef cattle with no adverse effects on feed utilization or rumen fermentation while the total bacterial population and C3 concentration increase.