Influence of flake fragmentation on the feeding value of steam-flaked corn in finishing diets for feedlot cattle

Two trials were conducted to evaluate the influence of fines on the feeding value of steam-flaked corn (SFC) in finishing diets for feedlot cattle. Three levels (0, 333 and 667 g/kg) of re-rolled SFC replaced standard SFC (0.31 kg/L) in a corn-based finishing diet (DM basis). Diets were offered as total mixed rations. Re-rolled SFC consisted of standard air-dry SFC that was passed through the rollers a second time to simulate loss of flake integrity which can occur during feed-handling. In experiment one, the influence of fines in SFC on growth performance was evaluated in eighteen crossbred steers (294 ± 5 kg) in a replicated 3 × 3 Latin square design. Daily weight gain was similar (P>0.10) among treatments, averaging 1.31 kg/d. Dry matter intake tended to be greater (quadratic effect, P=0.06) for diets containing re-rolled steam-flaked corn. Gain efficiency and dietary NE were not influenced by dietary treatments (P>0.10). In experiment two, six Holstein steers (308 ± 17 kg) with cannulas in the rumen and proximal duodenum were used in a replicated 3 × 3 Latin square design to evaluate treatment effects on characteristics of digestion. Reductions in particle size of SFC due to rerolling did not influence ruminal or total tract digestion of OM, NDF, N, or starch (P>0.10). Likewise, there were no treatment effects (P>0.10) on ruminal microbial efficiency, ruminal pH, or ruminal VFA molar proportions. It is concluded that the impact of flake disintegration during conveyance and handling on feedlot cattle growth performance and characteristics of digestion will be marginal, if appreciable.