The objective of this study was to evaluate the effects of the source of silage, cereal grain, and their interaction on growth performance, digestibility, and carcass characteristics of finishing beef cattle. Using a completely randomized design within an 89-d finishing study, 288 steers were randomly assigned to 1 of 24 pens (12 steers/pen) with average steer body weight (BW) within a pen of 464 kg ± 1.7 kg (mean ± SD). Diets were arranged in a 2 × 3 factorial with corn silage (CS) or barley silage (BS) included at 8% (dry matter [DM] basis). Within each silage source, diets contained dry-rolled barley grain (BG; 86% of DM), dry-rolled corn grain (CG; 85% of DM), or an equal blend of BG and CG (BCG; 85% of DM). Total tract digestibility of nutrients was estimated from fecal samples using near-infrared spectroscopy. Data were analyzed with pen as the experimental unit using the Mixed Model of SAS with the fixed effects of silage, grain, and the two-way interaction. Carcass and fecal kernel data were analyzed using GLIMMIX utilizing the same model. There were no interactions detected between silage and grain source. Feeding CG increased (P < 0.01) DM intake by 0.8 and 0.6 kg/d relative to BG and BCG, respectively. Gain-to-feed ratio was greater (P = 0.04) for BG (0.172 kg/kg) than CG (0.162 kg/kg) but did not differ from BCG (0.165 kg/kg). Furthermore, average daily gain (2.07 kg/d) and final body weight did not differ among treatments (P ≥ 0.25). Hot carcass weight (HCW) was 6.2 kg greater (372.2 vs. 366.0 kg; P < 0.01) and dressing percentage was 0.57 percentage units greater (59.53 vs. 58.96 %; P = 0.04) for steers fed CS than BS, respectively. There was no effect of dietary treatment on the severity of liver abscesses (P ≥ 0.20) with 72.0% of carcasses having clear livers, 24.4% with minor liver abscesses, and 3.6% with severe liver abscesses. Digestibility of DM, organic matter, crude protein, neutral detergent fiber, and starch were greater for BG (P < 0.01) than CG or BCG. As expected, grain source affected the appearance of grain kernels in the feces (P ≤ 0.04). Feeding CS silage increased the appearance of fractured corn kernels (P = 0.04), while feeding BS increased fiber appearance in the feces (P = 0.02). Current results indicate that when dry rolled, feeding BG resulted in improved performance and digestibility compared with CG and BCG. Even at low inclusion levels (8% of DM), CS resulted in improved carcass characteristics relative to BS.

Corn production in Western Canada has increased with development of short-season varieties partially offsetting the use of barley as a silage and grain source. The current study evaluated effects of silage and cereal-grain source on subcutaneous fat composition of finishing cattle. Steers (465 ± 28.0 kg) were assigned to 24 pens (12 steers/pen) in a 2 x 3 factorial design for an 89-d finishing study. Diets contained corn-silage (CS) or barley-silage (BS) at 8% (DM) combined with either dry rolled barley-grain (BG; 86% of DM), corn-grain (CG; 85% of DM), or an equal blend of barley- and corn-grain (BCG; 85% of DM). Bone-in ribeyes were collected from four steers-per-pen and subcutaneous fatty acids analyzed by gas chromatography. Feeding dry-rolled corn-grain increased dietary fat and 18:2n-6 concentrations resulting in small increases in 18:2n-6, total n-6 fatty acids, and n-6/n-3 ratios in subcutaneous fat (P < 0.05). There were no changes in proportions of major trans-18:1 isomers (t10-18:1 or t11-18:1), the main natural isomer of conjugated linoleic acid (c9,t11-18:2), or n-3 fatty acids. Substitution of dry rolled corn-grain for barley-grain in finisher diets can, therefore, be done without substantially altering the fatty acid composition of beef, including polyunsaturated fatty acid biohydrogenation products.

Five ruminally cannulated heifers were used in an incomplete 6 × 6 Latin square design to determine the effects of cereal silage (barley vs. corn), cereal grain (barley vs. corn vs. a 50:50 blend of barley and corn), and their interaction (S × G) on dry matter intake, ruminal fermentation, total tract digestibility, nitrogen balance, and in situ degradation. Corn silage (CS) or barley silage (BS) was included at 8% of dietary dry matter (DM). Within each silage source, diets contained (DM basis) either dry-rolled barley (BG; 86%), dry-rolled corn (CG; 85%), or an equal blend of barley and corn (BLEND; 85%). Periods were 25 d, with 5 d of dietary transition, 13 d of dietary adaptation, and 7 d of data and sample collection. Samples collected included feed and refusals, total urine and feces, and ruminal fluid. All data were analyzed using the Mixed model of SAS with the fixed effects of silage, grain, and the S × G. Dry matter intake (P ≥ 0.19) and mean ruminal pH (P ≥ 0.096) were not affected by the silage, grain, or S × G. Total short-chain fatty acid concentrations were greater for BLEND than BG or CG (grain, P = 0.003) and for CS (silage, P = 0.009) relative to BS. The molar proportion of acetate was greater for BS-BG and BS-CG (S × G, P &lt; 0.001), while molar proportion of propionate was greater for CS-BG (S × G, P &lt; 0.001) relative to other silage and grain source combinations. Rumen ammonia-N concentration was greater for CG than BG, or BLEND (grain, P &lt; 0.001), and greater for CS compared to BS (silage, P = 0.023). Apparent total tract digestibility of DM, organic matter, neutral detergent fiber, starch, and gross energy were greatest for BG (grain, P ≤ 0.035). Digestible energy content (Mcal/kg) was greater for BG (grain, P = 0.029) than CG and BLEND. Total nitrogen retention (g/d and % of intake) was greatest for CS-BG (S × G, P ≤ 0.033) relative to all other treatments. In situ degradation rates of DM, crude protein, and starch were greater for BG than CG (P ≤ 0.004). The potentially degradable fraction of DM, crude protein, and starch was greater for CG (P ≤ 0.031), while the undegradable fraction was greater for BG (P ≤ 0.046). For silage sources, CS had greater 24 h in situ DM digestibility (P = 0.009) and starch digestibility (24, 48, and 72 h incubations, P ≤ 0.034) relative to BS. Results suggest that while feeding a combination of CS and BG promotes propionate production and greater N retention; few other additive effects were observed.

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The objective was to determine the effects of feeding barley (BS) or corn (CS) silage with dry-rolled barley (BG), dry-rolled corn (CG), or a blend of barley and corn grain (BCG) on growth performance and nutrient digestibility predicted using near-infrared spectroscopy for backgrounding cattle. Steers (n = 288) were stratified by BW into 24 pens and pens were randomly assigned to 1 of 6 treatments (n = 4) in a 2 × 3 factorial design. Main factors included BS or CS in combination with BG, CG, or BCG. There were no silage × grain interactions. DMI (P = 0.018) and final BW (P = 0.004) were greater for steers fed CS than BS, but ADG (1.01 kg/d) and G:F (0.10 kg/kg) were not affected by silage or grain source. Steers fed CS also had greater DM, OM, CP, ADF, starch, and gross energy digestibility values (P < 0.01) than BS. Feeding BG increased starch, NDF, ADF, and CP digestibility values (P ≤ 0.01) over CG and BCG. Relative to BS, feeding CS increased DMI, ending BW and nutrient digestibility; while dry-rolled BG improved nutrient digestibility when compared to CG and BCG in backgrounding diets.