Effects of silage type and inclusion level on ruminal characteristics and feeding behavior of steers fed finishing diets.

Crossbred beef steers fitted with a ruminal cannula were used to study the effects of silage type (BH 8895 corn or AF7401 sorghum) and level of inclusion (10 or 20%) in beef cattle finishing diets on digestibility of nutrients, ruminal kinetics, in vitro methane production, and feeding behavior. A 4 × 6 unbalanced Latin square design was used (6 steers; 363 ± 23 kg; 4 diets: corn silage [CS] or sorghum silage [SS], both at 10 or 20% inclusion, DM basis). Each period consisted of 14 d of adaptation and 7 d of collection. Steers were fed once daily at 1000 h. An additional study evaluated the ruminal degradability of intact ensiled sorghum grain ruminally incubated in 3 steers (547 ± 56 kg BW), using the same hybrids from the main study from 10 laboratory experimental silos. The GLIMMIX procedures of SAS were used for statistical analyses. Steers fed SS had greater NDF intake ( < 0.01) compared with the ones fed CS. The magnitude of the NDF intake change depended on the level of inclusion ( < 0.01), which was 6 and 16% for 10 and 20% inclusion, respectively. Regardless the level of inclusion, CS diets promoted greater ( ≤ 0.01) apparent total tract digestibility of nutrients evaluated (DM, OM, NDF, ADF, hemicellulose, and starch) compared with SS diets. Steers fed SS diets tended to chew 1.1 h/d more ( = 0.07) than steers fed CS diets. The level of inclusion increased ( = 0.02) the chewing time per day by 1.3 h. No major differences were observed in any of the ruminal pH and in vitro gas production variables evaluated for silage type and inclusion level ( ≥ 0.09). The CS-fed steers had 12% greater total VFA concentration and an 18.5% lower ( < 0.01) acetate-to-propionate ratio compared with SS-fed steers. The acetate-to-propionate ratio was 16% greater ( < 0.01) when steers were fed SS compared with when steers were fed CS. The CS samples were more extensively ruminally degraded ( < 0.01) than the SS samples. Greater ( < 0.01) NDF ruminal disappearance was observed in ruminal environments containing 20% silage compared with those containing 10% silage. After 96 h inside the rumen, intact ensiled sorghum grain degradability of DM reached only 51.7%. Replacing CS with SS in beef finishing diets (low roughage inclusion) requires adjustments to balance dietary energy. Sorghum material induced a desirable roughage effect in feeding behavior but also offered the potential for improved regarding fiber digestibility and intact grain ruminal degradability.

Flint corn grain processing and citrus pulp level in finishing diets for feedlot cattle.

Four trials were conducted to evaluate the effects of flint corn processing and the replacement of corn with citrus pulp (CiP) in diets for Nellore feedlot cattle. In a 103-d finishing trial, 216 Nellore bulls (350 ± 24 kg initial BW) were used in a randomized complete block design with a 2 × 4 factorial arrangement of treatments. Factors included 2 processing methods, either ground corn (GC) or steam-flaked corn (FC), with CiP replacing each corn type at 4 levels (0, 25, 50, and 75% of DM). All diets contained 12% sugarcane bagasse and 88% concentrate (DM basis). Treatments were also evaluated in metabolism trials, in which 10 ruminally cannulated Nellore steers (389 ± 37 kg) were assigned to 2 independent but simultaneous 5 × 5 Latin squares, each using 1 method of corn processing (GC and FC). Interactions ( < 0.05) between corn processing and CiP inclusion level were observed for final BW, DMI, ADG, G:F, and HCW. With FC-based diets, added CiP linearly decreased final BW ( = 0.04), whereas with GC-based diets, added CiP quadratically increased final BW ( = 0.002). With FC-based diets, the inclusion of CiP linearly increased DMI ( = 0.03) and linearly decreased ADG ( = 0.03) and G:F ( = 0.001). Increasing CiP in GC-based diets quadratically increased DMI ( = 0.001), ADG ( = 0.005), and HCW ( = 0.003). In FC-based diets, CiP inclusion had no effect on HCW ( = 0.21). Dressing percent, LM area, and 12th-rib fat were not affected by diet ( ≥ 0.05). For steers fed GC diets, CiP inclusion in the diet quadratically decreased the molar proportion of isovalerate ( = 0.001) but linearly increased ruminal butyrate ( = 0.006). No differences ( ≥ 0.16) were observed for total VFA concentrations, acetate:propionate ratio, and ruminal NH-N as CiP replaced GC. For steers fed FC diets, the molar proportion of acetate linearly increased ( = 0.002) whereas the proportion of propionate was linearly decreased ( < 0.001), resulting in a linear increase ( = 0.001) in the acetate:propionate ratio. Replacing corn with CiP linearly reduced NEm ( = 0.001) and NEg ( < 0.001) of FC-based diets but did not affect ( = 0.15) NE values of CG-based diets. Steam flaking flint corn improved cattle performance in this trial more than has been reported for dent corn in the published literature.

Biofuel feedstock and blended coproducts compared with deoiled corn distillers grains in feedlot diets: Effects on cattle growth performance, apparent total tract nutrient digestibility, and carcass characteristics.

Crossbred steers (British × Continental; = 192; initial BW 391 ± 28 kg) were used to evaluate the effects of feeding ethanol coproducts on feedlot cattle growth performance, apparent nutrient digestibility, and carcass characteristics. Steers were blocked by initial BW and assigned randomly to 1 of 6 dietary treatments within block. Treatments (replicated in 8 pens with 4 steers/pen) included 1) control, steam-flaked corn-based diet (CTL), 2) corn dried distillers grains with solubles (DGS; DRY-C), 3) deoiled corn dried DGS (DRY-CLF), 4) blended 50/50 corn/sorghum dried DGS (DRY-C/S), 5) sorghum dried DGS (DRY-S), and 6) sorghum wet DGS (WET-S). Inclusion of DGS was 25% (DM basis). The DGS diets were isonitrogenous, CTL was formulated for 13.5% CP, and all diets were balanced for ether extract. Final shrunk BW, ADG, and DMI did not differ among CTL and DGS treatments ( ≥ 0.19). Overall G:F did not differ from CTL for DRY-C, DRY-CLF, or WET-S ( ≥ 0.12); however, G:F was 9.6% less for DRY-S compared with CTL ( < 0.01) and tended ( = 0.09) to be less for DRY-C/S than CTL. For grain source, ADG and G:F were less for DRY-S vs. DRY-C ( < 0.05), but blending DRY-C/S tended ( = 0.07) to increase ADG and increased ( = 0.05) carcass-adjusted G:F vs. DRY-S. For WET-S, final BW and ADG were greater ( < 0.05), and G:F tended ( = 0.06) to be greater than for DRY-S. There was no difference in ADG, DMI, or G:F of steers fed DRY-C vs. DRY-CLF ( ≥ 0.35). Apparent DM and OM digestibility did not differ for CTL, DRY-C, DRY-CLF, and WET-S ( ≥ 0.30) but were lower for DRY-C/S and DRY-S ( < 0.05). Nutrient digestibility was lower for DRY-S vs. DRY-C ( < 0.01), but apparent digestibility of OM, DM, NDF, ADF, CP, ether extract, and starch were increased ( < 0.01) for DRY-C/S vs. DRY-S. Although starch digestibility did not differ between DRY-S and WET-S ( 0.18), digestibility of other measured nutrients was greater for WET-S vs. DRY-S ( < 0.01). Ether extract digestibility was greater for DRY-CLF vs. DRY-C ( < 0.05). Carcass weight, dressing percent, and marbling score did not differ between CTL and DGS diets ( ≥ 0.23). For DRY-S, HCW was lower than for DRY-C ( = 0.02); however, compared with DRY-S, HCW tended to be greater for DRY-C/S ( = 0.10) and WET-S ( = 0.07). At a moderately high (25% DM) inclusion, blending C/S or feeding WET-S resulted in cattle growth performance and carcass characteristics similar to those of CTL and corn-based coproducts.