Digestibility, lactation performance, plasma metabolites, ruminal fermentation, and bacterial communities in Holstein cows fed a fermented corn gluten-wheat bran mixture as a substitute for soybean meal

The purpose of this research was to investigate the effects replacing soybean meal (SBM) with a fermented corn gluten-wheat bran mixture (FCWM) on nutrient digestibility, lactation performance, plasma metabolites, ruminal fermentation, and bacterial communities in Holstein cows. Nine healthy multiparous (parity = 3) cows similar body weights (624 ± 14.4 kg), days milk (112 4.2), yields (31.8 1.73 kg; all mean standard deviation) were used replicated 3 × Latin square design periods 28 d. Cows fed 1 dietary treatments which FCWM replaced SBM as follows: basal diet no replacement (0FCWM); 50% (50%FCWM); 100% (100%FCWM). diets formulated be isocaloric isonitrogenous. results showed that total-tract digestibility dry matter crude protein increased linearly FCWM, we found trend for neutral detergent fiber potentially digestible NDF digestibility. Milk yield tended increase linear manner more consumed, energy-corrected production significantly supplementation result lactose yields. Plasma glucose IgG concentrations increasing supplementation, but malondialdehyde concentration decreased linearly. Concentrations total volatile fatty acids propionate leading decrease pH. relative abundance Prevotellaceae, Veillonellaceae, Prevotella Succinivibrionaceae Muribaculaceae fecal Ruminococcaceae, Ruminococcaceae UCG-005 Peptostreptococcaceae Overall, altered composition community improved fermentation cows, providing data reference use dairy production.