Abstract
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.
395 Effects of supplemental protein and yeast on fermentation of low quality forage in single-flow continuous culture fermenters