Ruminant Nutrition Session II
Various anecdotes suggest the combination of supplemental protein and yeast improve utilization of low-quality forage. Two studies were conducted to evaluate effects of a commercially available supplement containing protein and yeast on fermentation in single-flow continuous culture fermenters. In Exp. 1, Bermuda grass with no supplement (NCON1), dried distillers grains (PCON1), and two commercially available supplements Diamond V XP (DV1) or SweetPro 16 (SP1) were compared. In Exp. 2, K31 tall fescue with no supplement (NCON2), supplemental dried distillers grains (PCON2), and two commercially available supplements Diamond V XP (DV2) or SweetPro 16 (SP2) were compared. Twenty-four single flow fermenters (1470mL) were randomly assigned to treatments and fed twice daily for 8 d, 5 d of adaptation and 3 d of collection. In both experiments, digestibility of DM, OM, NDF, and ADF were not influenced by supplementation regardless of source (P >0.10). In Exp. 1, NH3-N concentration increased (P< 0.01) for DV1 over both NCON1 and PCON1 and was greatest for SP1 (P< 0.01). Greater amounts of NH3-N and microbial N were recovered from fermenter overflow when SP1 was supplemented (P< 0.01). Crude protein (CP) degradation was also greatest for SP1; however, when supplement was included, regardless of source, CP degradation was increased over NCON1. Acetate, propionate, butyrate, and total VFA levels were similar (P >0.10) amongst NCON1, PCON1, and DV1 and greatest when SP1 was supplemented. In Exp. 2, fermenter NH3-N concentration was greatest for SP2 (P< 0.01) and similar amongst NCON2, PCON2, and DV2 (P >0.01). No differences were detected (P >0.10) between treatments with respects to CP degradation. Total VFA concentrations increased over time regardless of treatment during the second study.