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The objectives of this study were to investigate the effect of a saponin-based surfactant, Grain Prep surfactant (GP), and hot flake aging time on starch characteristics and ruminal DM and starch degradability of steam-flaked corn grain. In 2 experiments, the moisture content of incoming corn was automatically adjusted using the Grain Prep Auto Delivery System to 19.8% (Exp. 1) and 18.5% (Exp. 2). The application rate of GP was 22 mg/kg (as-is basis). Control corn was treated with water alone. Processed corn in Exp. 2 was stored in insulated containers for 0, 4, 8, or 16 h. Flaked corn samples were incubated in the rumen of lactating dairy cows for 0, 2, 4, 6, 16, or 24 h. In Exp. 1, GP increased, compared with the control, the soluble fraction and effective degradability (ED) of DM by 17.2 and 8.6%, respectively. The ED of cornstarch was increased by 6.7%. In Exp. 2, the concentration of soluble DM and starch were increased by GP by 15 and 24% compared with the control. The ED of DM and starch were also increased by 3 and 4%, respectively. No differences in gelatinization temperatures were observed due to treatment, except that GP-treated grain had a slightly greater mean gelatinization enthalpy in Exp. 2. In a pilot study, DM degradability parameters were not affected by germination of the corn kernels. Aging of the hot flakes for up to 16 h resulted in a quadratic decrease in DM and starch ruminal degradability. The aging process affected starch gelatinization enthalpy values of flaked grain in a manner opposite to that observed for ruminal DM and starch degradation. This phenomenon was most likely explained by increased starch intramolecular associations or crystallinity associated with starch annealing, or both. This study confirmed our previous observations that Grain Prep surfactant increases flaked corn DM and starch degradability in the rumen. Because the rate of degradation was not affected by the surfactant, the increase in degradability was attributed mainly to increases in DM and starch solubility.

Two experiments were conducted to study the effects of six processing techniques for barley grain in a 3 x 2 factorial arrangement of grain conditions and roller settings on ruminal degradation of the grain (Exp. 1) and on growth performance by 138 feedlot steers (n = 23 per treatment; Exp. 2). Dry barley (11% moisture, D barley), barley tempered to 20% moisture (M barley), and barley tempered with 60 mL/t of surfactant-based tempering agent (GrainPrep, Agrichem, Inc., Anoka, MN; MS barley), were each rolled at two roller settings selected from preliminary tests. The settings selected for the study were RD, the roller position that had yielded optimally processed D barley, and RMS, the setting that had yielded optimally processed MS barley. Setting RMS was tighter than RD. Barley rolled at the RMS setting was more extensively processed (i.e., had a lower [P 0.05) PI, percentage of whole kernels, or kernel thickness at either roller setting. The processing characteristics of tempered barley were unaffected (P > 0.05) by surfactant. The extent of in situ DM disappearance (ISDMD) was higher (P 0.05) ADG, DMI, or G:F during backgrounding, but improved (P < 0.01) these variables during finishing. Surfactant improved (P < 0.05) G:F but not DMI or ADG. The improvement in G:F was most pronounced when setting RMS was used. The optimal PI values calculated from performance data were numerically greater for the backgrounding diet than for the finishing diet. Steers fed M or MS barley had heavier (P < 0.01) hot carcasses and thicker (P < 0.05) fat cover but lower (P < 0.05) dressing percentages than steers fed D. When the feed barley was rolled at setting RMS, steers fed MS barley produced heavier (P < 0.05) carcasses than those fed M. Tempering with or without surfactant increased performance by feedlot steers compared with not tempering. Diet composition and degree of barley processing mediated this effect.

The objectives of this study were to investigate the effect of a saponin-based surfactant, Grain Prep surfactant (GP), and hot flake aging time on starch characteristics and ruminal DM and starch degradability of steam-flaked corn grain. In 2 experiments, the moisture content of incoming corn was automatically adjusted using the Grain Prep Auto Delivery System to 19.8% (Exp. 1) and 18.5% (Exp. 2). The application rate of GP was 22 mg/kg (as-is basis). Control corn was treated with water alone. Processed corn in Exp. 2 was stored in insulated containers for 0, 4, 8, or 16 h. Flaked corn samples were incubated in the rumen of lactating dairy cows for 0, 2, 4, 6, 16, or 24 h. In Exp. 1, GP increased, compared with the control, the soluble fraction and effective degradability (ED) of DM by 17.2 and 8.6%, respectively. The ED of cornstarch was increased by 6.7%. In Exp. 2, the concentration of soluble DM and starch were increased by GP by 15 and 24% compared with the control. The ED of DM and starch were also increased by 3 and 4%, respectively. No differences in gelatinization temperatures were observed due to treatment, except that GP-treated grain had a slightly greater mean gelatinization enthalpy in Exp. 2. In a pilot study, DM degradability parameters were not affected by germination of the corn kernels. Aging of the hot flakes for up to 16 h resulted in a quadratic decrease in DM and starch ruminal degradability. The aging process affected starch gelatinization enthalpy values of flaked grain in a manner opposite to that observed for ruminal DM and starch degradation. This phenomenon was most likely explained by increased starch intramolecular associations or crystallinity associated with starch annealing, or both. This study confirmed our previous observations that Grain Prep surfactant increases flaked corn DM and starch degradability in the rumen. Because the rate of degradation was not affected by the surfactant, the increase in degradability was attributed mainly to increases in DM and starch solubility.

Two experiments were conducted to study the effects of six processing techniques for barley grain in a 3 x 2 factorial arrangement of grain conditions and roller settings on ruminal degradation of the grain (Exp. 1) and on growth performance by 138 feedlot steers (n = 23 per treatment; Exp. 2). Dry barley (11% moisture, D barley), barley tempered to 20% moisture (M barley), and barley tempered with 60 mL/t of surfactant-based tempering agent (GrainPrep, Agrichem, Inc., Anoka, MN; MS barley), were each rolled at two roller settings selected from preliminary tests. The settings selected for the study were RD, the roller position that had yielded optimally processed D barley, and RMS, the setting that had yielded optimally processed MS barley. Setting RMS was tighter than RD. Barley rolled at the RMS setting was more extensively processed (i.e., had a lower [P0.001] processing index, PI), had lighter (P0.001) volume weight, thinner (P0.001) kernels, and fewer (P0.001) whole kernels compared with setting RD. Tempering did not affect (P0.05) PI, percentage of whole kernels, or kernel thickness at either roller setting. The processing characteristics of tempered barley were unaffected (P0.05) by surfactant. The extent of in situ DM disappearance (ISDMD) was higher (P0.01) in grain rolled at setting RMS compared with RD. At both roller settings, tempering reduced (P0.05) ISDMD between 4 and 24 h of ruminal incubation. Steers fed RMS-rolled barley had lower (P0.001) DMI, slightly lower (P = 0.084) ADG, but increased (P0.05) gain:feed (G:F) compared with steers fed RD-rolled barley. Tempering did not affect (P0.05) ADG, DMI, or G:F during backgrounding, but improved (P0.01) these variables during finishing. Surfactant improved (P0.05) G:F but not DMI or ADG. The improvement in G:F was most pronounced when setting RMS was used. The optimal PI values calculated from performance data were numerically greater for the backgrounding diet than for the finishing diet. Steers fed M or MS barley had heavier (P0.01) hot carcasses and thicker (P0.05) fat cover but lower (P0.05) dressing percentages than steers fed D. When the feed barley was rolled at setting RMS, steers fed MS barley produced heavier (P0.05) carcasses than those fed M. Tempering with or without surfactant increased performance by feedlot steers compared with not tempering. Diet composition and degree of barley processing mediated this effect.