Continental crossbred beef heifers were used in a randomized complete block design experiment to evaluate the effects of replacement of dry-rolled corn with unprocessed rye on the finishing-phase growth performance and efficiency of dietary net energy (NE) use. Fifty-six heifers (433 ± 34.0 kg) were transported 241 km from a sale barn in North Central South Dakota to the Ruminant Nutrition Center in Brookings, SD. Heifers were blocked by weight grouping and allotted to treatment pens (n = 7 heifers/pen and 4 pens/treatment). Treatments included a finishing diet that contained 60% grain (diet dry matter basis) as dry-rolled corn (DRC) or unprocessed rye grain (RYE). On study day 14, all heifers were consuming the final diet and were implanted with 200 mg of trenbolone acetate and 28 mg of estradiol benzoate (Synovex-Plus, Zoetis, Parsippany, NJ, USA). The RYE heifers had decreased (p ≤ 0.01) final body weight, average daily gain, and gain efficiency; however, they tended (p = 0.08) to have a greater dry matter intake compared to DRC heifers. RYE heifers had decreased (p ≤ 0.01) observed dietary NE and decreased (p ≤ 0.01) observed-to-expected dietary NE ratio for maintenance and gain compared to DRC heifers. The dressing percentage, 12th rib fat thickness, ribeye area, and the distribution of yield and quality grades were not altered (p ≥ 0.12) by dietary treatment. The hot carcass weight, calculated yield grade, estimated empty body fat (EBF), and body weight at 28% EBF decreased (p ≤ 0.02) and retail yield increased (p = 0.01) in RYE compared to DRC heifers. These data indicate that unprocessed rye is a palatable feed ingredient for inclusion in finishing diets for beef cattle and that rye inclusion only minimally influences the carcass quality grade. The feeding value of unprocessed rye is considerably less (21.4%) than that of dry-rolled corn using current standards and approximately 91% of the NE value of processed rye (processing index = 78.8%). Rye grain fed as processed or unprocessed grain has an NE value that is less than 90% of that of dry-rolled corn.

The objective of this research was to investigate the influence of maternal prepartum dietary carbohydrate source on growth performance, carcass characteristics, and meat quality of offspring. Angus-based cows were assigned to either a concentrate-based diet or forage-based diet during mid- and late-gestation. A subset of calves was selected for evaluation of progeny performance. Dry matter intake (DMI), body weight (BW), average daily gain (ADG), gain to feed (G:F), and ultrasound measurements (muscle depth, back fat thickness, and intramuscular fat) were assessed during the feeding period. Carcass measurements were recorded, and striploins were collected for Warner-Bratzler shear force (WBSF), trained sensory panel, crude fat determination and fatty acid profile. Maternal dietary treatment did not influence (p > 0.05) offspring BW, DMI, ultrasound measurements, percent moisture, crude fat, WBSF, or consumer sensory responses. The forage treatment tended to have decreased (p = 0.06) 12th rib backfat compared to the concentrate treatment and tended to have lower (p = 0.08) yield grades. The concentrate treatment had increased (p < 0.05) a* and b* values compared to the forage treatment. These data suggest variation in maternal diets applied in this study during mid- and late-gestation has limited influence on progeny performance.

The objective of this study was to determine the effects that increasing doses of encapsulated butyric acid and zinc (BZ) have on feedlot steer growth performance, rumen morphometrics and small intestine histology (data not statistically analyzed), dietary net energy utilization, and carcass characteristics. Steers [n = 272; shrunk body weight (BW) = 360 kg ± 74 kg] were assigned to dietary treatments [0 (CON), 1, 2, or 3 g BZ/kg diet dry matter] in a randomized complete block design (RCBD) with pen (n = 32 total; n = 8 per treatment) as experimental unit. Pens were blocked by cattle source and location within the feedyard. Cattle were fed until visually assessed to have 1.27 cm rib-fat and were shipped for harvest at a commercial beef abattoir. Carcass and liver health data were recorded. A subset of steers (n = 8 total; n = 2 per treatment) was harvested at the SDSU Meat Laboratory to collect empty body measurements, rumen samples for morphometric analysis, and duodenal and ileal samples for histological analysis to provide context to feeding trial outcomes. Feedlot growth performance data was calculated on a carcass-adjusted basis: hot carcass weight (HCW)/0.625. Data were analyzed as a RCBD with fixed effects of BZ inclusion level and block was considered a random effect; pre-planned contrasts for CON vs. BZ, plus linear, and quadratic responses were tested. No differences (P ≥ 0.11) were observed for final BW, dry matter intake, average daily gain (ADG), feed conversion efficiency (G:F), performance calculated dietary net energy, HCW, ribeye area, rib-fat thickness, marbling score, estimated empty body fat, or distribution of USDA yield grade (YG) 1, 3, 4, 5, and USDA quality grade among treatments. A tendency (P = 0.10) was observed for CON vs. BZ for calculated YG. Tendencies were detected for USDA YG 2 carcass distribution (linear; P = 0.07) and for normal and abscessed liver prevalence (quadratic; P = 0.08). Dressed yield tended to be greater (P = 0.08) for BZ vs. CON and increased with dose (linear; P = 0.05). Receiving period shrunk BW, ADG, and G:F was improved (P ≤ 0.02) for BZ-supplemented steers compared to CON. Data from this study suggests that the addition of BZ to feedlot finishing diets to improve receiving period growth performance and decreasing the prevalence of abscessed livers should be further investigated. Encapsulating butyric acid and zinc (BZ) can allow a timed release through the gastrointestinal tract (GIT) which can potentially improve rumen and intestinal epithelial health, as well as improve growth performance and carcass characteristics of cattle. We conducted a study to determine how increasing dietary inclusion of BZ affects feedlot steer growth performance, GIT health, and carcass traits. Four inclusion levels were tested in this experiment: 0, 1, 2, and 3 g BZ/kg diet (dry matter basis). Inclusion of BZ improved growth performance during the initial 28 d receiving period but did not alter growth performance for the cumulative feeding period. Only minor differences were observed for GIT health markers and carcass traits for steers supplemented BZ compared to non-supplemented steers. However, the prevalence of liver abscesses was quadratically affected by an increasing dose of BZ where 0 and 3 g BZ/kg had the highest prevalence and 1 and 2 g BZ/kg had the lowest prevalence. These data indicate that the use of BZ may be beneficial during the dietary adaptation period, and growth performance benefits may persist through the finishing period.

The objectives of the study were to evaluate the effects of substituting dried distillers’ grains with solubles (DDGS) with soybean meal (SBM) on nutrient and amino acid (AA) intake, flow, and digestibility. Red Angus steers (n = 4; body weight = 360 ± 9 kg) with ruminal, duodenal, and ileal cannulas were used in a 4 × 4 Latin square. Diets consisted of (DM basis) dry-rolled corn (70%), grass hay (10%), liquid supplement (5%), and test ingredients (15%). Treatments were (1) 15.0% DDGS (CON); (2) SBM in replacement of 50% of DDGS (SBM50); (3) SBM in replacement of 75% of DDGS (SBM75), and (4) SBM in replacement of 100% of DDGS (SBM100). Each period lasted 18 d, consisting of a 10-d diet adaptation followed by an 8-d collection period. Data were analyzed using the MIXED procedure of SAS, with treatment included as a fixed effect and period and steer as random effects. Linear, quadratic, and cubic contrasts were applied to assess the response patterns to varying levels of DDGS and SBM. Nitrogen intake (P = 0.038, quadratic) decreased from CON to the intermediate SBM inclusion levels (i.e., SBM50 and SBM75), and then increased to SBM100. The duodenal flow of nonfiber carbohydrates linearly decreased (P = 0.050) as SBM inclusion increased. The total tract digestibility of neutral detergent fiber exhibited a cubic pattern (P = 0.033), with the greatest value observed for CON, the lowest value for SBM50, and intermediate values for SBM75 and SBM100. The amount of essential (EAA) and non-essential (NEAA) AA reaching the small and large intestines were not affected by treatment (P ≥ 0.12). When DDGS was exclusively fed, most AA exhibited AA utilization indexes greater than 1.0, indicating a net ruminal gain. Conversely, AA utilization indexes were near 1.0 when SBM was the sole protein source, suggesting minimal net ruminal change for most AAs. Total tract digestibility of lysine tended to increase linearly (P = 0.058) with the inclusion of SBM, while tryptophan (P = 0.063) and arginine (P = 0.088) displayed a quadratic tendency, increasing from CON to SBM50 and SBM75 and then decreasing to SBM100. True intestinal digestibility of individual EAA varied from 79.5% for histidine to 89.1% for lysine, while for NEAA it varied from 70.4% for cysteine to 89.7% for tyrosine. This study demonstrated that the extent of absorption in the small intestine varied among AA, with lysine and arginine exhibiting greater small intestinal availability in finishing cattle. Ultimately, DDGS and SBM deliver similar metabolizable amino acids in beef cattle finishing diets. This allows producers to prioritize cost-effectiveness and regional availability when selecting a protein source.

Two randomized complete block design experiments evaluated the influence that varying degrees of ingredient inclusion accuracy in a finishing diet have on growth performance and carcass traits. Treatments included (1) normal inclusion tolerance with a 0.454 kg tolerance for all ingredients (CON) or (2) variable inclusion tolerance where each ingredient was randomly increased or decreased but the targeted as-fed quantity for the daily delivery was met (VAR). In Experiment. 1, black Angus heifers (n = 60; initial shrunk BW = 460 ± 26.2 kg) were used in a 112 d experiment. Ten pens in total (5 pens/treatment, 6 heifers/pen) were used. The targeted diet (DM basis) consisted of high-moisture ear corn (75%), dried distiller’s grains (20%), and a liquid supplement (5%). As-fed inclusion rates for DDGS and LS varied from formulated targets by −20, −15, −10, −5, 0, +5, +10, +15 or +20%. The HMEC inclusion was adjusted so that the targeted as-fed amount of the diet was delivered daily. Treatment did not alter ADG, DMI, G:F, HCW, dressing percentage, rib-eye area, rib fat, USDA marbling score, KPH, yield grade, retail yield, empty body fat, or body weight at 28% estimated EBF, nor liver abscess prevalence or severity (p ≥ 0.15). In Exp. 2, Charolais–Angus cross steers (n = 128; initial shrunk BW = 505 ± 32.1 kg) were used in a 94 d experiment. Steers were assigned to pens (8 pens/treatment; 8 steers/pen) and one of the two management strategies used in Exp. 1 was employed. Ractopamine HCl was fed (300 mg per head daily) during the final 28 d. Diets consisted of (DM basis) dry-rolled corn (63%), dried distiller’s grains plus solubles (15%), liquid supplement (5%), grass hay (7%), and corn silage (10%). Ingredient inclusions were randomized in the same manner as Exp. 1, except LS inclusion was held constant. Corn silage inclusion was adjusted so that the targeted as-fed amount of the diet was delivered each day. Steers from VAR had increased (p = 0.01) DMI, but similar (p = 0.75) ADG resulting in reduced (p ≤ 0.02) G:F and growth-performance-predicted Net Energy for maintenance and gain. Treatment did not influence (p ≥ 0.38) HCW, dressing percentage, rib-eye area, rib fat, KPH, yield grade, retail yield, empty body fat, or body weight at 28% estimated EBF. A tendency for an increased USDA marbling score (p = 0.08) was noted in VAR. Under the conditions of this experiment, randomly altering ingredient proportions can impact growth performance and efficiency measures depending upon the type of finishing diet fed.