Table 4.
Effect of Saccharomyces cerevisiae fermentation product (SCFP) supplementation on N metabolism in finishing beef heifers
| Item | Treatments1 | SEM | P-value | ||||
|---|---|---|---|---|---|---|---|
| Control | ANT | rSCFP | dSCFP | rdSCFP | |||
| Intake, kg/d | 275 | 268 | 266 | 285 | 296 | 18.9 | 0.07 |
| Flow to duodenum | |||||||
| Total N, g/d | 272 | 261 | 256 | 279 | 285 | 32.0 | 0.85 |
| Dietary N2, g/d | 113 | 107 | 115 | 132 | 130 | 17.8 | 0.71 |
| Microbial N, g/d | 151 | 147 | 135 | 139 | 149 | 19.5 | 0.81 |
| Microbial efficiency3 | 27.5 | 26.2 | 21.3 | 23.1 | 20.9 | 3.24 | 0.32 |
| Digestibility, % of intake | |||||||
| Ruminal (truly) | 56.3 | 57.4 | 54.9 | 52.1 | 52.5 | 5.68 | 0.92 |
| Intestinal | 69.4 | 71.5 | 70.9 | 69.7 | 76.3 | 7.03 | 0.93 |
| Total tract | 68.1 | 70.1 | 72.6 | 71.3 | 75.3 | 1.75 | 0.09 |
1Treatments: 1) control diet (no antibiotics, no SCFP addition), control plus 2) antibiotics (ANT; 330 mg monensin + 110 mg tylosin/d per heifer; top-dressed), 3) ruminal delivery of SCFP (rSCFP; 18 g/d per heifer; top dressed), 4) duodenal delivery of SCFP (dSCFP; 18 g/d per heifer; via duodenal cannula), or 5) combination of treatments #3 and #4 (rdSCFP; 18 g rSCFP + 18 g dSCFP/d per heifer).
2Feed N + endogenous N.
3Gram of microbial N/kg of OM truly fermented.