in cattle offered corn silage, grass silage, or whole-crop wheat Rumen fermentation, microbial protein synthesis, and nutrient flow to the omasum

ABSTRACT: Objectives were to determine the relative effect of feeding corn silage (CS), 19 fermented whole-crop wheat (FWCW), and urea-treated processed whole-crop wheat 20 (UPWCW) compared to grass silage (GS), each supplemented with concentrates, on 21 forage intake, ruminal fermentation, microbial protein synthesis, some plasma metabolites, 22 and ruminal and total tract digestibility in cattle. Four ruminally fistulated steers with a 23 mean BW 509 (SD 6.3) kg were used in a 4 × 4 Latin Square designed experiment with 24 each period lasting 21 d. The omasal sampling technique in combination with a triple 25 marker method was used to measure nutrient flows to the omasum with Co-EDTA, Yb-26 acetate, and indigestible NDF (INDF) as liquid, small particle, and large particle phase 27 markers, respectively. Microbial N flow was assessed from purine base concentrations. 28 Steers fed CS, FWCW, and UPWCW consumed 2.7, 2.4, and 2.6 kg/d more ( P < 0.05) 29 forage and total DMI, respectively, than those fed GS-based diets. Rumen pH (