Commercial implants can have different coating technologies, carriers, and hormone amounts resulting in different payout characteristics and impacts on cattle growth. Revalor-G (Merck Animal Health, Madison, NJ) and Synovex One Grass (Zoetis Inc., Kalamazoo, MI) implants were used in stocker steers to evaluate calf gains during a 90-day summer grazing season. Revalor-G contains 40 mg of trenbolone acetate and 8 mg of estradiol, is uncoated, and has a cholesterol carrier. Synovex One Grass contains 150 mg of trenbolone acetate and 21 mg of estradiol benzoate, and has a porous polymer coating that extends payout window. Steers (n = 242) were assigned to one of seven pastures, implanted on day 0, and then weighed with an overnight shrink on days 0, 44, and 91 of grazing. Total gains and average daily gains during each half of the grazing season were determined. Average daily gain and total body weight gain were not different based on implant type. Cattle with the Revalor-G implant had an average daily gain of 2.6 lb/day, while cattle with the Synovex One Grass implant gained 2.5 lb/day. Cattle with the Revalor-G implant had a total body weight gain of 222 lb, while cattle with the Synovex One Grass implant gained 220 lb. Body weight gain and average daily gain were not different between implants in either section of the grazing period. Cattle performance was similar regardless of hormone amount and coating technology for these implants when used during a short-duration grazing period with stocker steers.

Implants are a cost-effective tool to aid in growth enhancement in beef cattle. Implants are heavily used in feedlot systems, with moderate to high usage in grazing systems. Each implant has different payout characteristics, generally as a result of varying coating technologies. A new grass-based implant has come on the market with a long-duration payout window. The objective of this study was to evaluate two implants in stocker steers on a double-stocked 90 d grazing season. The two implants were Revalor®-G (REV; Merck Animal Health, Summit, NJ) and Synovex® One Grass (SYN; Pfizer Animal Health, New York NY) which should have a quick payout and extended payout, respectively. Steers (n = 241) were weighed with an overnight shrink prior to turnout, midpoint, and end of grazing period. At initial weigh date steers were implanted with respective implants and assigned to one of seven pastures in a completely randomized block design with pasture as block. Within each pasture cattle on both implants grazed together. Performance was evaluated for total gains, gains in the first ½ of the season, and in the second ½ of the grazing season. Average daily gain was not different (P = 0.35) based on implant type (1.16 ± 0.02 kg/d for REV and 1.13 ± 0.02 kg/d for SYN). Total BW gain was not different (P = 0.72; 100.95 ± 2.27 kg for REV vs 99.63 ± 2.27 lb for SYN). Additionally, BW gain and ADG were similar (P > 0.43) between implants in both the early grazing (first 44 d) and late grazing season (d 45 – 90). Overall, cattle performance was similar regardless of coating technology in implants in a short duration grazing period with stocker steers. Cost is a factor in selecting implants in this management system. The SYN implant costs $4.95/animal while REV costs $1.38/implant. Due to similar performance and the lower cost of the implant, Revelor®-G provides the more economical implant strategy for a double stock 90 d grazing system found in the Flint Hills of Kansas.

A total of 1,866 cross-bred heifers (268 ± 9 kg initial BW) were used in a 181-d finishing study to evaluate the effects of time of terminal implant administration on growth and carcass measures. All heifers received an initial implant containing 80 mg of trenbolone acetate and 8 mg of estradiol (Revalor-IH, Merck Animal Health, Madison, NJ) at initiation of the experiment. Cattle were fed in 24 pens using a randomized complete block design. There were a total of six blocks, with arrival date serving as the blocking factor. The four treatments were achieved by administration of a subsequent implant containing 200 mg of TBA and 20 mg of estradiol (Revalor-200) at 160, 120, 80 or 40 d before harvest (DBH). Marketing dates of blocks of heifers were determined at initiation of the experiment and were based on expected growth performance of the heifers using historical data for the facility. All animals that died or were removed from the study were excluded from the analysis. Dry matter intake was similar (P ≥ 0.12) between all treatments. A quadratic response to treatment was observed for G:F (P = 0.02), HCW (P = 0.03), and LM area (P = 0.01), and a tendency for a quadratic response to treatment was observed for ADG (P = 0.07) and dressing percentage (P = 0.06). For all of these variables, the greatest numeric treatment values were observed for the 120 and 80 DBH treatments. Based on an axis of symmetry analysis for the regression lines, HCW was optimized at 94 DBH and G:F was optimized at 90 DBH. In addition to these observations, linear increases in marbling score (P = 0.03) and percentage of carcasses grading USDA Prime (P = 0.02) were observed as DBH treatment decreased. These results indicate that the optimal time to give a terminal implant to heifers based on G:F and HCW is between 90 and 94 DBH. However, the earlier in the finishing period that the terminal implant was given, the greater the negative impact on intramuscular fat deposition.

Crossbred heifers (n = 3,780; initial BW = 309 ± 55 kg) were utilized in a serial harvest experiment to compare the effects of two growth-promoting implant programs on feedlot performance and carcass characteristics. A traditional heifer re-implant program consisting of a Revalor-IH (80 mg trenbolone acetate [TBA] and 8 mg estradiol) at experiment initiation followed by a Revalor-200 (200 mg TBA, 20 mg estradiol) on day 90 was compared with a single Revalor-XH at experiment initiation. Revalor-XH contains 200 mg TBA and 20 mg estradiol in a proprietary coated extended-release formulation, with 4 uncoated pellets consisting of 80 mg TBA and 8 mg estradiol, and 6 coated pellets consisting of 120 mg TBA and 12 mg estradiol. Heifers were harvested after 172, 193, and 214 days-on-feed (DOF) resulting in a 2 x 3 factorial arrangement of treatments (2 implant treatments, 3 serial harvest groups). Heifers were assigned randomly into 54 pens with 70 heifers/pen, resulting in 9 replications/treatment. Revalor-XH heifers were not removed from their pens during the experiment. There were no implant treatment x serial harvest interactions (P > 0.05) for carcass-adjusted performance or carcass characteristics. Increasing DOF resulted in a linear increase (P < 0.03) in carcass-adjusted final BW, HCW, dressing percentage, and percent USDA Prime and Choice carcasses, and a linear decrease (P ≤ 0.01) in ADG, DMI, G:F, and percent USDA Select carcasses. Percentage of heifers reaching USDA yield grade 4 and 5 increased (P ≤ 0.01) with increasing DOF. Based on changes in live BW and HCW as DOF progressed, the proportion of live BW gain captured as HCW (carcass transfer) was 80%. Carcass-adjusted final BW (P = 0.06) and HCW (P = 0.09) tended to be greater for Revalor-IH/200 heifers than for Revalor-XH heifers. Dry matter intake tended (P = 0.06) to be greater, and ADG (P = 0.03) and G:F (P < 0.01) were lower for Revalor-XH heifers than for Revalor-IH/200 heifers. Dressing percentage (P = 0.21) and USDA quality grade distribution (P > 0.16) were not affected by implant treatment. Revalor-XH heifers produced more (P < 0.01) USDA Yield Grade 4 and 5 carcasses than Revalor-IH/200 heifers, with no differences (P > 0.15) in USDA Yield Grade 1, 2, or 3 carcasses. Compared to a Revalor-IH/200 implant strategy, heifers implanted with Revalor-XH had 1.2% lower ADG and 2.0% lower G:F while producing similar USDA quality grades. These data indicate that utilizing Revalor-XH is a viable alternative to re-implanting in feedlot heifers.

The objectives of this experiment were to determine (1) the effect of a Ralgro implant administered at 30 to 90 d of age on suckling-phase growth rate and weaning weight and (2) the effect of a Revalor-G implant at weaning on postweaning performance. A total of 194 suckling steer calves weighing 111 ± 25.6 kg at branding from 3 locations were used. Within location, steer calves were stratified by cow age and then randomly assigned to 2 experimental treatments: implanted with Ralgro (IMPL; n = 97) or no implant (NIMP; n = 97). At weaning, IMPL steers were reimplanted with Revalor-G. The steers were weighed at the time of branding, at weaning, after the preconditioning period, and after the stocker phase. Implanted steers gained 9 kg more (P < 0.01) BW between the branding and weaning dates compared with NIMP. This resulted in a 3.2% increase (P < 0.01) in actual weaning weight and a 6.6% increase (P < 0.01) in 134-d BW gain. One location yielded no difference (P > 0.5) in the preconditioning period; however, a 35.7% increase (P = 0.01) in IMPL ADG was recorded in the other 2 locations. In the wheat stocker phase, ADG was improved by 14.9% (P < 0.001) over NIMP. Ralgro growth-promoting implants remain an effective and economical method to increase performance of suckling steer calves, and the response is similar to research results published in the 1980s. Likewise, Ralgro followed by a Revalor-G implant allows for faster rates of BW gain and heavier final BW after weaning.

This study determined if zilpaterol hydrochloride (ZH) altered muscle metabolism and lipid components of 10 muscles. Crossbred heifers were either supplemented with ZH (n = 9) or not (Control; n = 10). Muscle tissue was collected (adductor femoris, biceps femoris, gluteus medius, infraspinatus, latissimus dorsi, longissimus dorsi, pectoralis profundi, semitendinosus, subscapularis, trapezius) immediately following carcass splitting. The mRNA abundance of AMPkɑ, IGF-I, MHC-I, IIA and IIX, β1-adrenergic receptor (βAR) and β2AR was determined, as well as, cross-sectional area and proportion of myosin isoforms, β1AR, β2AR, β3AR, nuclei, and satellite cell density. Furthermore, neutral (NL) and polar lipid (PL) fatty acids (FA) were quantified (mg/g). Zilpaterol hydrochloride decreased MHC-IIA mRNA (P = 0.007). In addition, ZH decreased total nuclei and β1AR and increased MHC-IIX cross-sectional area (P ≤ 0.021). Quantity of NL FA were not affected by ZH (P ≥ 0.173). However, among PL FA the ratio of PUFA:SFA was greater with ZH (P = 0.048). Muscle type impacted mRNA concentration of AMPkɑ, IGF-I, MHC-I, IIA, IIX, and β1AR mRNA concentration (P ≤ 0.037). Furthermore, the fiber type proportion, fiber cross-sectional area, and the densities of nuclei, β1AR, β2AR, β3AR, and satellite cells were influenced by muscle type (P ≤ 0.030). Total NL FA were affected by muscle (P ≤ 0.046). Meanwhile, total PL FA did not differ due to muscle (P = 0.242). However, prominent PL FA,18:0, 18:1 trans, and 18:2 n-6 were each greater (P < 0.05) among the oxidative subscapularis compared with glycolytic semitendinosus and adductor femoris. Overall, these data reveal that ZH impacts muscle metabolism and myogenic activity that establishes protein deposition. Meanwhile, ZH did not alter triglyceride content (NL), but cell membrane saturation (PL) was influenced, in accordance with alterations to muscle fiber type. Muscle also influenced muscle fiber type and lipid components. Therefore, muscle biology is greatly influenced by muscle but also through dietary inclusion of ZH.

Light weight stocker calves often experience health problems shortly after arrival to feeding facilities. Preventative health programs are routinely administered to calves upon arrival to reduce the incidence of Bovine Respiratory Disease. The major route of vaccine administration in cattle is via injection through either intramuscular or subcutaneous routes. Several products have been introduced that utilize the intranasal route of vaccine administration. There are several reasons why intranasal vaccine administration may be more beneficial: 1) Intranasal vaccine administration alleviates concerns that injections pose for Beef Quality Assurance programs. 2) Intranasal vaccine administration may be less stressful on the animal. 3) Intranasal vaccine administration delivers the vaccine to the site of infection in the case of respiratory pathogens, and may provide a different adaptive immune response to the vaccine.

Angus crossbred steers (n = 40; 563 ± 44 kg) were used to examine the effects of handling method and fat thickness on the blood chemistry and physiology of market steers. Steers were blocked by backfat (BF) thickness and were randomly assigned to treatment groups: low-stress handling (LSH) and aggressive handling (AH). Cattle were then ran¬domly assigned to one of 5 blocks containing 4 steers from the LSH and AH treatments. Steers in the LSH treatment were walked and AH cattle were run through a course of 1,540 m. Blood samples were obtained via jugular venipuncture before handling (BASE), at 770 m (LAP1), at 1,540 m (LAP2), and at1 h (1H) and 2 h (2H) after finishing the course. Blood samples were analyzed for plasma lactate (LAC), creatinine kinase (CK), base excess (BE), blood pH (pH), serum cortisol (CORT) concentrations, and venous carbon dioxide (PvCO2) and oxygen (PvO2) pressures. Heart rate (HR), respiratory rate (RR), and rectal temperature (TEMP) were measured at the same intervals. Cattle in the AH treatment had greater ( < 0.05) LAC than those in LSH at BASE (4.1 vs. 3.0 mmol/L), LAP1 (16.5 vs. 2.3 mmol/L), LAP2 (22.3 vs. 2.4 mmol/L), 1H (7.2 vs. 2.7 mmol/L), and 2H (4.0 vs. 2.5 mmol/L), respectively. Creatinine kinase and RR were not different (P > 0.14). Blood pH in AH cattle was decreased compared with that in LSH cattle ( < 0.05) at LAP1 (7.25 vs. 7.45) and LAP2 (7.19 vs. 7.48) but was not different ( > 0.13) at BASE, 1H, or 2H. Heart rate and TEMP were increased in AH cattle compared to LSH ( > 0.01). Serum cortisol was increased ( < 0.05) in AH compared to that in LSH cattle at LAP1 (87.5 vs. 58.9 nmol/L), LAP2 (144.4 vs. 93.1 nmol/L), and 1H (113.5 vs. 53.1 nmol/L). Although RR was not differ¬ent between LSH and AH, PvCO2 was decreased in AH compared to that in LSH ( < 0.05) at LAP2 (30.6 vs. 39.3 mmHg) and PvO2 was increased at LAP1 (42.7 vs. 33.5 mmHg) and at LAP2 (51.5 vs. 36.6 mmHg). Lactate was increased in AH cattle in the thicker BF group at 1H ( < 0.05), and blood pH was decreased at LAP1, LAP2, and 1H ( < 0.05) compared to the thinner BF cohorts. Four AH steers became exhausted (EXH) and did not complete the course. Increased CK, decreased PvCO2, and muscle tremors occurred in EXH steers compared to non-exhausted AH cohorts. Results of this study show that AH causes physiologic and blood chemistry changes in steers, which can be potentially detrimental to cattle, emphasizing the need for low-stress handling practices.

Fish and fish products are widely distributed feed in aquaculture and agriculture. However, still little is known on the lipid composition of them, potential differences in the lipid profiles of various meals depending on fish composition of meal and process technology. Therefore, the aim of this study was to determine the characteristics of polar and neutral lipids in selected meals. The thirteen fish meals were analyzed using two mass spectrometry technique coupled with gas chromatography and liquid chromatography. The highest lipid content was detected in mixed meal prepared from many species – multi fish meal – (mackerel, trout, sprat, herring, perch, silver carp etc.). In our article for the first time such precise fatty acid profile including atypical acids, e.g. branched fatty acid, was described in fish meals. Polyunsaturated fatty acids (PUFA) dominated in Norsea Mink (Nsm), Mauretania Grade (MG), Human Grade Batch (HGB) and Low Temperature (LT) products, what was associated with the processing technique and whole fish was used for meal production. These products were also abundant in phospholipids. Meals did not subjected to extrusion process and without addition of antioxidant were characterized by low levels of n-3 PUFA and small diversity of polar and neutral lipids.

receiving beef heifers health of receiving beef heifers

receiving beef heifers performance of receiving beef heifers

Two experiments were conducted to determine the effect of corn processing method and corn wet distillers grains plus solubles (WDGS) level on steer performance and metabolism. In Exp. 1, 480 crossbred steer calves (314 +/- 18 kg of BW) were used in a finishing experiment with a randomized complete block design and a 3 x 4 treatment structure. Diets were based on dry-rolled (DRC), high-moisture (HMC), or steam-flaked corn (SFC) with increasing levels of WDGS (0, 15, 27.5, or 40%; DM basis). A corn processing x WDGS level interaction (P < 0.01) was observed for ADG and G:F. Average daily gain and G:F increased linearly (P < 0.01) in steers fed DRC; ADG increased quadratically (P = 0.04) and G:F increased linearly (P = 0.02) in steers fed HMC; and ADG decreased quadratically (P = 0.02) with no change in G:F (P = 0.52) in steers fed SFC as WDGS increased. In Exp. 2, 7 ruminally fistulated steers (440 +/- 41 kg of BW) were used in a 6-period crossover design with 3 x 2 factorial treatment structure. Diets were the same as those fed in Exp. 1, except they contained only 2 levels of WDGS (0 or 40% of diet DM). Total tract starch digestibility was greater (P < 0.01) for steers fed SFC than for steers fed DRC or HMC. Minimum ruminal pH was less (P < 0.01) for steers fed SFC than for steers fed HMC or DRC. Variance of ruminal pH was different among all 3 processing methods with DRC < HMC < SFC (P < 0.10). In situ 22-h DM digestibility of DRC and HMC and starch digestibility of DRC were greater (P < 0.10) in steers fed DRC compared with steers fed HMC or SFC. Steers fed 0% WDGS had less (P < or = 0.02) intake of DM, OM, NDF, and ether extract compared with steers fed 40% WDGS. Total tract digestibility of DM and OM was greater (P < or = 0.08) and digestibility of ether extract tended (P = 0.11) to be less for steers fed 0% WDGS compared with steers fed 40% WDGS. Maximum ruminal pH and pH variance were greater (P < or = 0.08) in steers fed 0% WDGS. A corn processing x WDGS level interaction (P = 0.09) was observed for ruminal acetate to propionate ratio (A:P). Within diets containing 0% WDGS, A:P in steers fed SFC was less (P < or = 0.08). In diets containing 40% WDGS, A:P was similar between processing methods and not different from the SFC with 0% WDGS. The corn processing x WDGS level interaction observed in the finishing experiment may be due to the decreased ruminal A:P in DRC and HMC diets with 40% WDGS.

Sixteen crossbred heifers were used in completely randomized design to determine the effects of melengestrol acetate (MGA) on polymorphonuclear leukocyte (PMN) L-selectin and β2-integrin expression and leukocyte numbers in heifers following Escherichia coli endotoxin (LPS) injection. On d 0, cattle were stratified by weight and randomly assigned, within strata, to diets they were fed throughout the trial. The diets consisted of 53.4% concentrate, 46.6% alfalfa hay, and either 0 or 0.5 mg MGA per

Three experiments were conducted examining the effects of feeding different levels of dried distillers grains (DDG) and different proportions of condensed distillers solubles (CDS) added to DDG on performance and digestibility in forage-fed steers. In Exp. 1, a total of 120 individually fed crossbred steers (276 +/- 31 kg) were used in a randomized complete block design with a 4 x 5 factorial arrangement of treatments. Factors included DDG supplementation level (0.25, 0.50, 0.75, or 1.0% of BW daily) and proportion of CDS in DDG (0.0, 5.4, 14.5, 19.1, and 22.1% of DDG DM). A basal diet of 58.8% alfalfa hay, 39.2% sorghum silage, and 2% vitamin and mineral supplement (DM basis) was fed for ad libitum intake. As the level of DDG increased, intake of forage decreased linearly (P < 0.01), intake of DDG increased linearly (P < 0.01), and total DMI increased quadratically (P = 0.06). A DDG level x CDS level interaction (P < 0.01) was observed for ADG and G:F. The 0.0, 5.4, 14.5, 19.1, and 22.1% CDS treatments had the greatest ADG when DDG was supplemented at 0.75, 1.0, 1.0, 0.75, and 0.50% of BW daily, respectively. In Exp. 2, four crossbred steers (295 +/- 19 kg) were used in a 3-period switchback design. A basal diet of 58.8% alfalfa hay, 39.2% brome hay, and 2% vitamin and mineral supplement (DM basis) was fed at 95% of ad libitum intake. Treatments were DDG containing 0.0 or 22.1% CDS supplemented at 1.0% of BW daily. Apparent total tract digestibility was measured by total fecal collection. No differences between treatments were observed for digestibility of DM, OM, or NDF (P >/= 0.14). Digestibility of ether extract was greater (P = 0.02) in steers supplemented with DDG containing 22.1% CDS. In Exp. 3, two ruminally and duodenally cannulated Holstein steers (663 +/- 24 kg) were used to estimate DM and CP digestion of the DDG fed in Exp. 1 using the mobile bag technique. Basal diets were the same as fed in Exp. 1 and steers were supplemented with DDG at 0.5% of BW daily. Ruminal DM digestibility increased linearly (P < 0.01), and postruminal and total tract DM digestibility increased quadratically (P = 0.02 and P = 0.03, respectively) as the level of CDS increased. Level of CDS may affect growing steer performance because depressions in ADG and G:F were observed as intake of ether extract increased. A clear explanation for the interaction between the DDG supplementation level and the CDS level on growing steer performance was not evident in the digestion experiments.

Two experiments were conducted at the Kansas State University Beef Cattle Research Center to determine the effects of ractopamine-HCl (Optaflexx) on growth performance, carcass characteristics, and meat quality of finishing feedlot heifers. In Exp. 1, heifers implanted with Revalor-H (n = 302, initial BW = 479 kg) were fed steam-flaked corn diets with 0 (control) or 200 mg of ractopamine-HCl (OPT) per heifer daily for 28 d before slaughter. Average daily gain and DMI were not different between treatments (P > 0.17); however, OPT cattle tended to have a greater G:F (P = 0.06). Treatments did not differ with respect to final BW, HCW, dressing percentage, USDA yield grade, USDA quality grade, marbling score, LM area, KPH, Warner-Bratzler shear force, weight loss during cooking, or L*, a*, or b* colorimetric values during a 7-d retail display or purge loss from loin steaks during retail display (P > 0.19). In Exp. 2, nonimplanted crossbred heifers (n = 281, BW = 451 +/- 2 kg) were fed finishing diets based on steam-flaked corn. A control diet (no ractopamine) was compared with diets providing 200 mg of OPT per heifer daily for periods of 28 or 42 d (200 x 28 and 200 x 42, respectively), 300 mg/d for 28 d (300 x 28), and a step-up regimen consisting of 14 d at 100 mg, followed by 14 d at 200 mg, and the final 14 d at 300 mg of OPT (step-up). Feeding OPT had no effect on carcass weight gain among treatments (P = 0.18). The efficiency of carcass gain was 34 and 35% greater (P = 0.06) for the 200 x 42 and step-up groups compared with control, respectively. Feeding OPT at 300 mg for 28 d reduced DMI compared with the control, 200 x 28, and 200 x 42 (P < 0.05) groups. Administration of OPT had no effect on marbling score, yield grade, LM area, KPH, or percentages of carcasses grading USDA Choice (P > 0.10). Feeding ractopamine-HCl (Optaflexx) to finishing heifers generally improved the efficiency of carcass gain with minimal effect on carcass characteristics. These effects were most pronounced in heifers fed ractopamine for 42 d.

One hundred eighty-one Boer-sired goat kids from dams of predominantly Spanish breeding (17.6 ± 2.34kg initial BW; 177 wethers, 4 doelings) were used to determine optimum inclusion level of concentrate in diets fed to goats in confinement. Effects of elevated loafing areas on performance were also examined. Goats were blocked by weight (2 blocks per treatment) and randomly assigned to 1 of 12 outdoor pens (4.3m2; 15 to 16 head/pen) with concrete floors. Pens of goats were randomly assigned, within block, to 1 of 6 treatments. A 2 × 3 factorial arrangement was used with factors consisting of pen configuration, defined as the presence or absence of a concrete structure (45cm high, 75cm wide, and 150cm long) in the center of the pen, and level of concentrate in the diet (50, 70, or 90%). Goats were fed diets ad libitum twice daily for 126 d. Dry matter intake decreased linearly (P < 0.01) and gain efficiency increased linearly (P = 0.03) as the proportion of concentrate in the diet increased. Average daily gain (P < 0.01) and final BW (P = 0.02) responded quadratically to concentrate level, and were greatest for goats fed 70% concentrate. Presence of an elevated loafing area in the pen tended to decrease DMI (P = 0.09). Increasing the level of concentrate in the diet generally improved performance of Boer-crossbred goat kids fed in confinement.

Manipulation of cattle diets has been proposed as a possible preharvest control measure for Escherichia coli O157. Altering hindgut fermentation through diet changes may be a means to reduce fecal shedding of E. coli O157. In Exp. 1, the objective was to determine whether fecal shedding of E. coli O157 was related to fecal starch concentration. Beginning on d 20, and every week thereafter until d 61, steers in 54 pens (6 to 7 steers per pen) were sampled (n = 122) by fecal collection and rectoanal mucosal swabs (RAMS) for E. coli O157 and fecal starch concentration determinations. Escherichia coli O157 prevalence was 3.3% in fecal samples, 4.1% as measured by RAMS, and 4.9% by fecal or RAMS samples. Steers positive for E. coli O157 contained 21% more (P < 0.05) fecal starch than steers that were negative for E. coli O157. In Exp. 2, we attempted to alter the concentration of starch escaping rumen fermentation by feeding finishing diets based on steam-flaked corn (SFC) and dry-rolled corn (DRC) to 30 heifers prescreened for being culture positive for fecal E. coli O157. Beginning on d 13, heifers were sampled (feces and RAMS) weekly to monitor fecal pH and starch concentration, and prevalence of E. coli O157. Prevalence of E. coli O157 remained above 30% for the first 13 d, but declined (P < 0.05) over the entire 7-wk period. Based on RAMS, the prevalence of E. coli O157 tended to be greater (P = 0.08) for heifers fed SFC than for those fed the DRC diet. After d 20, heifers fed DRC had greater (P < 0.05) fecal starch and lower (P < 0.05) fecal pH than heifers fed SFC. Fecal pH was negatively correlated (r = - 0.34; P < 0.05; n = 143) with fecal starch concentration. Fecal starch concentration and pH were not different (P > 0.05) for heifers that were positive or negative for E. coli O157. Our data suggest that fecal shedding of E. coli O157 was not related to fecal pH or starch concentration in cattle fed grain-based diets.

Processing cereal grains generally increases starch digestion and improves feed efficiency and/or gain. However, the supply and cost effectiveness of using either wet corn gluten feed (WCGF) or wet distillers grains plus solubles (WDGS) is likely to increase in the future. Therefore, understanding how grain processing interacts with these byproducts will be critical for feedlots. Feeding wet byproducts improves performance compared to feeding dry byproducts, and the wet byproducts will likely be more commonly used and at greater inclusions compared to dry byproducts. When feeding WCGF, corn processing is more beneficial than in diets without WCGF. Cattle fed steam-flaked corn (SFC) were 14.6% more efficient than cattle fed dry-rolled corn (DRC) across three experiments. Cattle fed high-moisture corn (HMC) were 8.1% more efficient than cattle fed DRC in these experiments. These data suggest that processing corn as either HMC or SFC may be more beneficial in diets containing WCGF at 22 to 32% of diet DM. These data suggest that HMC and SFC are considerably better than DRC and even more so than in diets without WCGF. Interestingly, there does appear to be an interaction between corn processing and feeding WDGS. Unlike diets without WDGS, feeding DRC and HMC in combination with WDGS results in better performance than feeding SFC in combination with WDGS. However, performance differences are likely related to inclusion of WDGS. In one experiment evaluating 0, 15, 27.5, or 40% WDGS in diets based on either DRC, HMC, or SFC, the optimum inclusion was different between corn processing methods. We conclude that if diets are based on SFC, then the optimum inclusion of WDGS is likely 15 to 20% of diet DM. With diets comprised of DRC or HMC, the optimum inclusion of WDGS is 40% or 27.5 to 40%, respectively, for optimal gains and feed efficiency.