Search

Genomic testing of feeder cattle is reported to be beneficial in selecting cattle for the feedlot, as well as making management and marketing decisions. The objective of this study was to determine differences in performance and efficiency of finishing steers with a range of Neogen Igenity Beef scores for average daily gain (ADG) and milk. Spring born steer calves from the Oklahoma State University Range Cow Research Center (n = 83, BW = 419 ± 31.9) of Angus ancestry were placed on feed at the Willard Sparks Beef Research Center on May 5, 2022, after grazing wheat pasture for 155 d. The steers were grouped based on Igenity ADG Score [low (1-4), medium (5-6), or high (7-10)] and Milk Score [low (1-5) or high (6-10)] based on the Igenity results. Steers were allocated into pens (n = 5 steers/pen) in heavy and light BW blocks. Steers were fed a step-up diet for 30 d before being switched to a finishing ration diet (8% prairie hay, 20% Sweet Bran and 62% dry-rolled corn). Cattle were fed ractopamine for 30 d before slaughter. The heavy block were on feed for 119 d, while the light block were on feed for 148 d. Data were analyzed as a randomized complete block design using the mixed procedure of SAS (SAS Inst. Inc., Cary NC) with pen as the experimental unit. Steers with high growth (HG) scores gained weight more rapidly during finishing and weighed more at slaughter than medium growth (MG) and low growth (LG; P < 0.01); while steers with high milk (HM) gained faster (P < 0.01) and tended (P = 0.06) to be heavier at slaughter than low milk (LM). Growth score was shown to have an effect on dry matter intake (P < 0.01) with HG consuming more feed than MG or LG. Cattle with HM scores were less efficient than LM scores (P = 0.01), but there was no difference (P = 0.37) in feed efficiency due to ADG score. Those with high growth and milk scores had a higher average daily gain (P < 0.01). These data indicate that Igenity ADG scores can be used to select cattle with higher performance and bodyweight at slaughter with no adverse effect on feed efficiency. Steers with higher Igenity Milk scores were less efficient than those with LM scores. Igenity Milk scores can be used to predict efficiency, according to these data.

Our objective was to determine the effect of calf-fed or yearling finishing systems on the performance of dairy-beef crossbred steers. Dairy-beef hybrid steers were acquired from Land O’ Lakes Calf Milk Research Facility at Grey Summit, Missouri at 12-weeks of age and transported to Willard Sparks Beef Research Center (WSBRC). Upon arrival at WSBRC, steers were weighed, vaccinated, treated for parasites, and implanted with 36 mg of zeranol (Ralgro). Alternating groups of steers were placed either directly on finishing diets (FIN) or on high-quality pasture and supplementation for 5 to 6 mo before returning to WSBRC for finishing (GRW/FIN). Once GRW/FIN steers reached 312 ± 7 kg, the steers were returned to WSBRC, weighed, and processed. At WSBRC, steers within each finishing system were sorted by BW into 4 to 5 animal pens. Steers in FIN were re-implanted with Ralgro on d 56, Component TE-IS (80-mg trenbolone acetate,6-mg estradiol, and 29-mg tylosin tartrate; Elanco US, Greenfield, IN) on d 112, and Component TE-S (200-mg progesterone, 20-mg estradiol benzoate, 29-mg tylosin tartrate; Elanco) on d 224. Steers in GRW/FIN were implanted with Component TE-IS at the start of finishing, and Component TE-S on d 20. Steers in FIN were grown on successively greater energy growing diets through d 112, stepping up to a 20% roughage growing diet (18.4% CP and 2.4 Mcal NEg/kg from d 28 to 112. On d 112, FIN steers were transitioned to a finishing diet consisting of 12% roughage, 12% crude protein, and 1.3 Mcal NEg/kg. A final finishing diet (8% prairie hay, 20% Sweet Bran and 62% dry-rolled corn) was fed to FIN steers from d 224 to slaughter. Steers in GRW/FIN were stepped up to the finishing diet when they reached 407 ± 6 kg. Finishing diets for the final 28 d for FIN and GRW/FIN included ractopamine hydrochloride at a rate of 300 mg·steer-1·d-1. Initial and terminal BW were greater (P < 0.01) in steers in the GRW/FIN finishing system. Body weight at reimplant was greater (P < 0.01) for FIN. Steers in the GRW/FIN system were on feed for fewer (P < 0.01) days compared with FIN steers. Average daily gain (ADG) and DMI (kg·steer-1·d-1) were greater (P < 0.01) for GRW/FIN. Steers in GRW/FIN had a greater (P ≤ 0.02) feed:gain ratio than those placed directly into a finishing system. There were no differences (P ≥ 0.10) in USDA Yield Grade, marbling, ribeye area (REA), or back-fat thickness (BFT) between finishing systems. Steers in FIN had a greater (P < 0.01) dressing percentage (DP) and lighter (P ≤ 0.01) hot carcass weight (HCW) than those for GRW/FIN. Finishing system has an impact on performance and efficiency of dairy-beef hybrid steers, but minimal impact on carcass quality.

Two experiments (EXP1 and EXP2) evaluated the effects of NutraGen (NG) on calf health following exposure to bovine viral diarrhea virus (BVDV) on d -3 and Mannheimia haemolytica (Mh) infection on d 0. For each EXP, steers (BW = 251 ± 38.2 kg) were randomly allocated to 1 of 3 treatments (TRT). Treatments included a placebo (CON; EXP1 n = 5; EXP2 n = 5), a placebo fed from d -18 to d -3 followed by NG fed from d -3 to d 28 (CHLG; EXP1 n = 5; EXP2 n = 6), and NG fed from d -18 to d 28 (PREC; EXP1 n = 6; EXP2 n = 5). There was no treatment by time interaction (TRT×TME) or TRT effect for rectal temperatures (RT) or clinical scores (CS) in EXP1 or CS in EXP2 (P ≥ 0.26). There was a TRT×TME for respiration rates (RR) during the first 24 h following Mh infection (P = 0.04), and a tendency for a TRT effect from d -3 to d 14, and overall in EXP1 (P ≤ 0.10). There was a tendency for a TRT×TME for RT from d -3 to d 14 in EXP2 (P = 0.04). There was a TRT effect for RR from d -3 to d 14 and overall in EXP2 (P ≤ 0.05). There was a TRT×TME for leukocytes during the first 24 h following Mh infection in EXP1 (P = 0.03) and overall in both EXP (P ≤ 0.001). There was no TRT×TME or TRT effect for neutrophils (NEU), lymphocytes (LYM), or NEU:LYM in EXP1 (P ≥ 0.19); however, there were multiple TRT×TME and TRT effects for NEU, LYM, and NEU:LYM in EXP2 (P ≤ 0.05). These experiments suggest that NG has the potential to alter clinical and cellular responses during a bovine respiratory disease challenge.

Our objectives were to determine how pre-finishing plane of nutrition, season, and breed of beef sire affect performance, efficiency, and carcass attributes of dairy-beef hybrid calves. Dairy × beef hybrid steers (3 to 7 d of age) were maintained on either a moderate plane of nutrition or high plane of nutrition from 0 to 12 wk of age. Calves (n = 211, BW = 122 ± 16 kg) were then transported 689 km to the OSU Sparks Beef Research Center at an average age of 92 ± 1.6 d in four blocks. Calves from predominantly Holstein dairies in the Midwest were sired by Angus (n = 147) or Continental breed (n = 64) sires. Steers were processed on arrival and were sorted by BW within previous treatment into 4 to 5 head pens and fed receiving diets. Steers were transitioned to a grower diet from d 14 to 112. Steers were fed a 12% roughage finishing diet from d-112 to 224. A final 8% roughage finishing diet was fed from d 224 to slaughter with ractopamine hydrochloride (300 mg·steer-1·d -1) included the last 28-d before harvest. Increasing plane of nutrition during the milk replacer and starter feeding period increased (P ≤ 0.03) initial BW at arrival and through d 84, but was not affected (P ≥ 0.08) thereafter. Calves received during the winter and spring were heavier (P < 0.01) on arrival through d 168 and at harvest and gained BW faster during the growing phase and final finishing phase than steers received during the summer. Steers sired by Angus sires were heavier throughout finishing (P < 0.01) and gained BW more rapidly (P < 0.01) than steers sired by Continental breeds. Breed of sire and season have a large impact on performance of finishing dairy × beef hybrids.

Five studies were conducted to evaluate the effects of lipid source on performance and health of stressed feeder cattle. A total of 332 heifers (195 +/- 2.37 kg initial BW) in trial 1 and 336 heifers (206 +/- 1.70 kg initial BW) in trial 2 were fed diets containing ground flaxseed (FLAX), rolled full-fat soybeans (SOY), or tallow (TAL) at 13, 20, or 4%, respectively (DM basis). All diets were formulated to be isonitrogenous and isocaloric. The ADG and G:F for the first 7 d and for the entire feeding period were greater (P < 0.05) for TAL and FLAX than for SOY. Percentage of animals treated and retreated for bovine respiratory disease did not differ among dietary treatments. The FLAX treatment increased (P < 0.05) total n-3 PUFA concentrations in the plasma, whereas SOY increased (P < 0.05) plasma concentrations of total n-6 PUFA. In trial 3, 18 steers were individually fed diets containing TAL and 18 steers were fed a diet containing SOY (20% of DM). In trials 4 and 5, 18 steers were individually fed diets containing TAL and 18 steers were fed diets containing FLAX (12.9% of DM). On d 14 and 17 of study 3, 4, and 5, 16 steers from each dietary treatment were injected i.v. with Escherichia coli O55:B5 lipopolysaccharide (LPS), and 2 steers from each diet were injected with saline. Rectal temperatures after LPS challenge were lower (P < 0.05) for SOY and FLAX than for TAL, and plasma TNF was greater (P < 0.05) for SOY than for TAL. Serum haptoglobin and blood fibrinogen increased and white blood cell count decreased in response to LPS, but none of these variables was affected by treatment. Although this research failed to measure an effect of lipid source on feedlot morbidity or mortality, these studies indicate that altering the source and type of dietary fatty acids may modify the immune response in stressed feeder cattle and that performance may be hindered by feeding full-fat soybeans to receiving cattle.

One-hundred ninety-two crossbred steers (initial BW = 351 ± 11 kg) were used to determine the effects of removing alfalfa hay (AH) from dry-rolled corn-based diets containing wet corn gluten feed (WCGF) on animal performance and nutrient (N and OM) mass balance in open feedlot pens. Steers were stratified by weight and assigned randomly to 24 pens (2 × 3 factorial) and fed for 132 d from June to October 2002. Experimental diets contained either 0 or 35% WCGF and 0, 3.75, or 7.5% AH, and were formulated to be isonitrogenous. For efficiency of gain, an interaction occurred (P = 0.09) between AH and WCGF. Feed effi- ciencies of cattle fed 35% WCGF were improved 4.4% (P = 0.10) compared with efficiencies of cattle fed no WCGF at 0% AH; there was a marked improvement in ADG for cattle fed WCGF compared with no WCGF in diets with 0% AH. Within 35% WCGF diets, efficiency decreased as AH inclusion increased (P = 0.06). Effi- ciency was equal across AH levels when 0% WCGF was fed; however, ADG was decreased when AH was removed. Interactions between AH and WCGF were not detected for other performance or carcass criteria; therefore, main effects of AH and WCGF are discussed.

Twelve ruminally cannulated Jersey steers (BW = 534 kg) were used in an incomplete Latin square design experiment with a 2 x 2 factorial arrangement of treatments to determine the effects of wet corn gluten feed (WCGF) and total DMI level on diet digestibility and ruminal passage rate. Treatments consisted of diets formulated to contain (DM basis) steam-flaked corn, 20% coarsely ground alfalfa hay, and either 0 or 40% WCGF offered once daily for ad libitum consumption or limited to 1.6% of BW (DM basis). Two consecutive 24-d periods were used, each consisting of 18 d for adaptation, 4 d for collection, and a 2-d in situ period. Rumens of all steers were evacuated once daily at 0, 4, 8, and 12 h after feeding. Chromic oxide (10 g/[steer*d]) was fed as a digestibility marker, and steers were pulse-dosed with Yb-labeled alfalfa hay to measure ruminal particulate passage rate. Dacron bags containing 5 g of steam-flaked corn, WCGF, or ground (2-mm screen) alfalfa hay were placed into the rumens of all steers and removed after 3, 6, 12, or 48 h. Wet corn gluten feed increased percent apparent total-tract digestion of OM (P < 0.01), NDF (P < 0.01), and starch (P < 0.03), decreased (P < 0.01) ruminal total VFA concentration, increased (P < 0.01) ruminal NH3 concentration, and increased (P < 0.01) ruminal pH. Wet corn gluten feed also increased (P < 0.01) ruminal passage rate of Yb. Limit feeding decreased (P < 0.01) percent apparent total-tract digestion of both OM and NDF, ruminal total VFA concentration (P < 0.01), and ruminal fill (P < 0.01), but increased (P < 0.01) ruminal NH3 concentration. Apparent total-tract digestion of starch was not affected (P = 0.70) by level of DMI. A DMI level x hour interaction (P < 0.01) occurred for ruminal pH. Limit feeding increased ruminal pH before and 12 h after feeding, but decreased ruminal pH 4 h after feeding compared with diets offered ad libitum. A diet x DMI level interaction (P < 0.02) occurred for in situ degradation of alfalfa hay, with dietary addition of WCGF increasing (P < 0.02) the extent of in situ alfalfa hay degradation in steers fed for ad libitum consumption. This study suggests that WCGF increases OM and NDF digestion, and that limit feeding diets once daily might depress OM and NDF digestion, possibly due to decreased stability of the ruminal environment.

Three finishing trials were conducted to determine the effects of dietary manipulation and management on N losses from open feedlots. In each experiment, 96 steers were assigned randomly to 12 nutrient balance pens. In Trial 1, calves were fed for 180 d during the winter/spring months; in Trial 2, yearlings were fed for 132 d in the summer. In Trials 1 and 2, N losses from pens were compared directly by adding OM to the pen surface or indirectly by feeding digestible ingredients designed to increase OM excretion. The dietary treatment (BRAN) included 30% corn bran (DM basis) replacing dry-rolled corn. Pens where OM was directly added received sawdust applications (SAWDUST) at a rate to match OM excretion from the BRAN diet. These two treatments were compared with a conventional, 75% dry-rolled corn diet (CON). Because CON and SAWDUST diets were identical, performance for both treatments was similar during Trials 1 and 2. The BRAN diet decreased (P < 0.10) gain efficiency during Trials 1 and 2 by 9.5% relative to CON. Fecal N excretion was greater (P < 0.01) for calves and yearlings when BRAN was fed compared with CON. Adding OM to the pen surface increased (P < 0.01) the amount of N in manure removed from pens and reduced (P < 0.10) N losses in Trial 1. Nitrogen losses were not significantly different among treatments in Trial 2. In Trial 3, calves were fed for 166 d during the winter/spring months. A 2 x 2 factorial design was used to evaluate pen cleaning frequency and diets similar to CON and BRAN. Pens were either cleaned monthly or once at the end of the feeding period. Daily DMI was greater (P = 0.01) and ADG was lower (P < 0.01) when cattle were fed BRAN compared with CON. Responses from all three trials indicate a negative effect of BRAN on gain efficiency. Dietary treatment and cleaning frequency interacted for N balance in the feedlot. Nitrogen losses decreased and manure N increased (P < 0.10) for cattle fed BRAN compared with CON when pens were cleaned monthly. Feeding BRAN did not affect total manure N, but resulted in higher N losses when pens were cleaned only once. For all trials, BRAN increased the amount of N remaining in composted manure. Adding OM to pen surfaces and/or cleaning pens more frequently may decrease N losses from open feedlot pens and from compost, although responses seem influenced by ambient temperature or season.

Six ruminally cannulated Angus-cross steers (362 kg) were used in a replicated 3 x 3 Latin square design to determine effects of supplementing Maillard reaction products (MRP) on acid-resistant E. coli and coliform populations. Steers were fed roughage-based diets supplemented (DM basis) with either 10% soybean meal (SBM), 10% nonenzymatically browned SBM (NESBM), or 10% SBM top-dressed with 45 g of a lysine-dextrose Maillard reaction product (LD-MRP). Equal weights of dextrose, lysine hydrochloride, and deionized water were refluxed to produce the LD-MRP. The NESBM was manufactured by treating SBM with invertase enzyme, followed by heating to induce nonenzymatic browning. Steers were allowed slightly less than ad libitum access to diets fed twice daily and were adapted to their respective treatments within 10 d. On d 11, ruminal and fecal samples were collected at 0, 2, 4, 6, 8, and 12 h after feeding from each of the steers and transported to the laboratory for microbial analysis. Ruminal samples and feces were analyzed for pH and VFA, and both ruminal fluid and feces were tested for acid-resistant E. coli and total coliforms by incubating samples in tryptic soy broth adjusted to pH 2, 4, and 7. Ruminal pH and total VFA concentrations did not differ among treatments. The molar proportion of ruminal acetate was higher (P < 0.05) for steers receiving NESBM than for steers receiving SBM and LD-MRP. At pH 4, steers that received NESBM had lower (P < 0.05) ruminal populations of E. coli and total coliforms than steers that received SBM. No differences were observed for ruminal E. coli and total coliforms at pH 2 and 7. Fecal pH was lower (P < 0.05) for steers fed NESBM than for steers fed SBM or LD-MRP. Molar proportions of fecal acetate were lower (P < 0.05) and proportions of butyrate and isovalerate were higher (P < 0.05) for steers fed NESBM compared with steers fed SBM. Fecal E. coli at pH 4 was lower (P < 0.05) for steers fed NESBM than for steers fed LD-MRP. Fecal E. coli and total coliforms at pH 2 and 7 did not differ among treatments. Dietary MRP had limited effectiveness at decreasing acid-resistant coliforms in the rumen and feces of cattle. Acid resistance in coliforms may depend on protein availability.

One finishing trial and one digestibility trial were used to evaluate wet corn gluten feed (WCGF) and alfalfa hay (AH) combinations in steam-flaked corn (SFC) finishing diets. In Exp. 1, 631 crossbred heifers (initial BW = 284 +/- 7.9 kg) were fed SFC-based diets containing combinations of WCGF (25, 35, or 45% of diet DM) and AH (2 or 6% of dietary DM) in a 2 x 3 factorial arrangement of treatments. No interactions existed between WCGF and AH for heifer performance. Increasing dietary WCGF linearly decreased gain efficiency (P < 0.01), dietary NEg concentration (P < 0.05), and 12th-rib fat thickness (P = 0.10). Cattle fed 35% WCGF had the lowest occurrence of abscessed livers, resulting in a quadratic response (P < 0.05) as dietary WCGF increased. In Exp. 2, 12 ruminally cannulated Jersey steers (585 kg) were fed SFC-based diets containing combinations of WCGF (25 or 45% of diet DM) and AH (0, 2, or 6% of diet DM) in an incomplete Latin square design with a 2 x 3 factorial arrangement of treatments. Starch intake was lower (P < 0.05), but NDF intake was greater (P < 0.05) as AH and WCGF increased in the diet. Ruminal pH was increased by AH (linear, P < 0.05) and tended (P < 0.07) to increase with WCGF. Feeding 2% AH led to the greatest ruminal NH3 but the lowest total VFA and propionate (quadratic, P < 0.05). Addition of AH to diets containing 25% WCGF increased acetate to a greater extent than addition to diets containing 45% WCGF (AH x WCGF interaction, P < 0.05). Feeding 45% WCGF tended to increase passage rate (P = 0.17) and decrease (P < 0.05) total tract OM digestibility but increase (P < 0.05) in situ degradation of DM from AH and WCGF. Interactions between AH and WCGF existed (P < 0.05) for ruminal fluid volume (quadratic effect of AH x WCGF level), in situ SFC degradation (linear effect of AH x WCGF level), and in situ rate of WCGF DM disappearance (quadratic effect of AH x WCGF level). We conclude that AH levels may be decreased when WCGF is added to SFC diets as 25% or more of the dietary DM.

Two experiments were conducted to evaluate the effects of alfalfa hay (AH) and wet corn gluten feed (WCGF) combinations on ADG and gain efficiency of cattle limit-fed growing diets. In Exp. 1, crossbred beef steers (n = 220; initial BW = 262 kg) were limit-fed diets consisting of steam-flaked corn and 40% WCGF (DM basis) with 0, 10, or 20% ground AH (0AH, 10AH, and 20AH, respectively). A fourth diet containing 20% ground AH and steam-flaked corn served as a control. All diets were fed once daily at 1.8% of BW (DM basis). Growing period ADG, gain efficiency, and dietary NE calculated from performance data de- creased linearly (P < 0.01) with addition of AH to diets containing WCGF. Rate of DMI increased linearly (P < 0.05) with AH addition to diets containing WCGF. Following the growing period, steers were finished on a commondietofferedadlibitum.Gainefficienciesduring the finishing period were higher (P < 0.05) for steers fed the 20AH diet than for steers fed the control diet. In Exp. 2, crossbred beef heifers (n = 339; initial BW = 277 kg) were limit-fed diets containing steam-flaked corn with 10, 20, or 30% ground AH and 0, 40, or 68% WCGF in a 3 × 3 factorial arrangement, fed once daily

Crossbred beef steers (n = 615) were used in a 152-d experiment to compare steam-flaked corn (SFC) diets containing 0, 30, or 60% wet corn gluten feed (WCGF). On d 114 to 118, ruminal and fecal samples were collected from 180 steers and analyzed for pH, VFA, and total and acid-resistant Escherichia coli and coliforms. Acid resistance of E. coli and coliform populations was determined by exposure of the samples for 1 h in pH 2, 4, and 7 citric acid/sodium phosphate buffers. Increasing levels of WCGF linearly decreased total ruminal VFA (P = 0.01) and total fecal VFA (P = 0.06), but linearly increased ruminal and fecal acetate:propionate (P < 0.01) ratio and ruminal and fecal pH (P < 0.05). Feeding increasing WCGF levels resulted in a quadratic response (P < 0.05) with respect to numbers of ruminal E. coli and total coliform populations resistant to pH 4 exposure. Steers fed 30% WCGF had higher (0.7 log units) ruminal E. coli and total coliforms after exposure at pH 4 compared to steers fed 0 or 60% WCGF. Populations of E. coli and total coliforms at pH 2 and 7 were similar for all dietary treatments. Dietary WCGF linearly increased DMI (P = 0.07) and liver abscesses (P = 0.03) and linearly decreased dietary NEg (P = 0.02). Average daily gain and feed efficiencies were greatest when steers were offered 30% WCGF (quadratic, P < 0.05). Dietary manipulations that reduce acid concentrations may not correspond to changes in acid resistance of E. coli and total coliform populations detected in the gastrointestinal tracts of cattle. Moderate levels of WCGF complement SFC finishing diets.

Five studies were conducted to evaluate the effects of lipid source on performance and health of stressed feeder cattle. A total of 332 heifers (195 +/- 2.37 kg initial BW) in trial 1 and 336 heifers (206 +/- 1.70 kg initial BW) in trial 2 were fed diets containing ground flaxseed (FLAX), rolled full-fat soybeans (SOY), or tallow (TAL) at 13, 20, or 4%, respectively (DM basis). All diets were formulated to be isonitrogenous and isocaloric. The ADG and G:F for the first 7 d and for the entire feeding period were greater (P0.05) for TAL and FLAX than for SOY. Percentage of animals treated and retreated for bovine respiratory disease did not differ among dietary treatments. The FLAX treatment increased (P0.05) total n-3 PUFA concentrations in the plasma, whereas SOY increased (P0.05) plasma concentrations of total n-6 PUFA. In trial 3, 18 steers were individually fed diets containing TAL and 18 steers were fed a diet containing SOY (20% of DM). In trials 4 and 5, 18 steers were individually fed diets containing TAL and 18 steers were fed diets containing FLAX (12.9% of DM). On d 14 and 17 of study 3, 4, and 5, 16 steers from each dietary treatment were injected i.v. with Escherichia coli O55:B5 lipopolysaccharide (LPS), and 2 steers from each diet were injected with saline. Rectal temperatures after LPS challenge were lower (P0.05) for SOY and FLAX than for TAL, and plasma TNF was greater (P0.05) for SOY than for TAL. Serum haptoglobin and blood fibrinogen increased and white blood cell count decreased in response to LPS, but none of these variables was affected by treatment. Although this research failed to measure an effect of lipid source on feedlot morbidity or mortality, these studies indicate that altering the source and type of dietary fatty acids may modify the immune response in stressed feeder cattle and that performance may be hindered by feeding full-fat soybeans to receiving cattle.

One-hundred ninety-two crossbred steers (initial BW = 351 +/- 11 kg) were used to determine the effects of removing alfalfa hay (AH) from dry-rolled corn-based diets containing wet corn gluten feed (WCGF) on animal performance and nutrient (N and OM) mass balance in open feedlot pens. Steers were stratified by weight and assigned randomly to 24 pens (2 x 3 factorial) and fed for 132 d from June to October 2002. Experimental diets contained either 0 or 35% WCGF and 0, 3.75, or 7.5% AH, and were formulated to be isonitrogenous. For efficiency of gain, an interaction occurred (P = 0.09) between AH and WCGF. Feed efficiencies of cattle fed 35% WCGF were improved 4.4% (P = 0.10) compared with efficiencies of cattle fed no WCGF at 0% AH; there was a marked improvement in ADG for cattle fed WCGF compared with no WCGF in diets with 0% AH. Within 35% WCGF diets, efficiency decreased as AH inclusion increased (P = 0.06). Efficiency was equal across AH levels when 0% WCGF was fed; however, ADG was decreased when AH was removed. Interactions between AH and WCGF were not detected for other performance or carcass criteria; therefore, main effects of AH and WCGF are discussed. Daily intake, ADG, and HCW increased linearly (P0.05) as dietary AH level increased. Feeding 35% WCGF also resulted in greater DMI (P0.01) and a tendency for greater ADG and HCW (Por = 0.10) compared with steers fed no WCGF. Interactions between AH and WCGF were not observed for feedlot N mass balance. As level of AH increased across diets, N intake, N retention, and N excretion increased (P0.05). Steers fed 35% WCGF consumed and excreted more N (P0.01) than those fed no WCGF. More manure DM (P = 0.11), OM, and N (P0.01) were removed from pens housing steers fed 35% WCGF as well as greater OM and N recovery in finished compost. More N (kilogram/steer) was also lost to volatilization as a result of greater N excretion when WCGF was fed. Expressed as a percentage of N excretion, loss of N from pens housing steers fed 0 and 35% WCGF was not different, averaging nearly 80%. These data suggest that AH has less value when dry-rolled corn-based diets contain 35% WCGF and can be decreased from conventional levels. Furthermore, loss of N from open feedlot pens is high during the summer months, and feeding WCGF may not reduce N losses during these times of year.

Twelve ruminally cannulated Jersey steers (BW = 534 kg) were used in an incomplete Latin square design experiment with a 2 x 2 factorial arrangement of treatments to determine the effects of wet corn gluten feed (WCGF) and total DMI level on diet digestibility and ruminal passage rate. Treatments consisted of diets formulated to contain (DM basis) steam-flaked corn, 20% coarsely ground alfalfa hay, and either 0 or 40% WCGF offered once daily for ad libitum consumption or limited to 1.6% of BW (DM basis). Two consecutive 24-d periods were used, each consisting of 18 d for adaptation, 4 d for collection, and a 2-d in situ period. Rumens of all steers were evacuated once daily at 0, 4, 8, and 12 h after feeding. Chromic oxide (10 g/[steer*d]) was fed as a digestibility marker, and steers were pulse-dosed with Yb-labeled alfalfa hay to measure ruminal particulate passage rate. Dacron bags containing 5 g of steam-flaked corn, WCGF, or ground (2-mm screen) alfalfa hay were placed into the rumens of all steers and removed after 3, 6, 12, or 48 h. Wet corn gluten feed increased percent apparent total-tract digestion of OM (P0.01), NDF (P0.01), and starch (P0.03), decreased (P0.01) ruminal total VFA concentration, increased (P0.01) ruminal NH3 concentration, and increased (P0.01) ruminal pH. Wet corn gluten feed also increased (P0.01) ruminal passage rate of Yb. Limit feeding decreased (P0.01) percent apparent total-tract digestion of both OM and NDF, ruminal total VFA concentration (P0.01), and ruminal fill (P0.01), but increased (P0.01) ruminal NH3 concentration. Apparent total-tract digestion of starch was not affected (P = 0.70) by level of DMI. A DMI level x hour interaction (P0.01) occurred for ruminal pH. Limit feeding increased ruminal pH before and 12 h after feeding, but decreased ruminal pH 4 h after feeding compared with diets offered ad libitum. A diet x DMI level interaction (P0.02) occurred for in situ degradation of alfalfa hay, with dietary addition of WCGF increasing (P0.02) the extent of in situ alfalfa hay degradation in steers fed for ad libitum consumption. This study suggests that WCGF increases OM and NDF digestion, and that limit feeding diets once daily might depress OM and NDF digestion, possibly due to decreased stability of the ruminal environment.

Three finishing trials were conducted to determine the effects of dietary manipulation and management on N losses from open feedlots. In each experiment, 96 steers were assigned randomly to 12 nutrient balance pens. In Trial 1, calves were fed for 180 d during the winter/spring months; in Trial 2, yearlings were fed for 132 d in the summer. In Trials 1 and 2, N losses from pens were compared directly by adding OM to the pen surface or indirectly by feeding digestible ingredients designed to increase OM excretion. The dietary treatment (BRAN) included 30% corn bran (DM basis) replacing dry-rolled corn. Pens where OM was directly added received sawdust applications (SAWDUST) at a rate to match OM excretion from the BRAN diet. These two treatments were compared with a conventional, 75% dry-rolled corn diet (CON). Because CON and SAWDUST diets were identical, performance for both treatments was similar during Trials 1 and 2. The BRAN diet decreased (P0.10) gain efficiency during Trials 1 and 2 by 9.5% relative to CON. Fecal N excretion was greater (P0.01) for calves and yearlings when BRAN was fed compared with CON. Adding OM to the pen surface increased (P0.01) the amount of N in manure removed from pens and reduced (P0.10) N losses in Trial 1. Nitrogen losses were not significantly different among treatments in Trial 2. In Trial 3, calves were fed for 166 d during the winter/spring months. A 2 x 2 factorial design was used to evaluate pen cleaning frequency and diets similar to CON and BRAN. Pens were either cleaned monthly or once at the end of the feeding period. Daily DMI was greater (P = 0.01) and ADG was lower (P0.01) when cattle were fed BRAN compared with CON. Responses from all three trials indicate a negative effect of BRAN on gain efficiency. Dietary treatment and cleaning frequency interacted for N balance in the feedlot. Nitrogen losses decreased and manure N increased (P0.10) for cattle fed BRAN compared with CON when pens were cleaned monthly. Feeding BRAN did not affect total manure N, but resulted in higher N losses when pens were cleaned only once. For all trials, BRAN increased the amount of N remaining in composted manure. Adding OM to pen surfaces and/or cleaning pens more frequently may decrease N losses from open feedlot pens and from compost, although responses seem influenced by ambient temperature or season.

Six ruminally cannulated Angus-cross steers (362 kg) were used in a replicated 3 x 3 Latin square design to determine effects of supplementing Maillard reaction products (MRP) on acid-resistant E. coli and coliform populations. Steers were fed roughage-based diets supplemented (DM basis) with either 10% soybean meal (SBM), 10% nonenzymatically browned SBM (NESBM), or 10% SBM top-dressed with 45 g of a lysine-dextrose Maillard reaction product (LD-MRP). Equal weights of dextrose, lysine hydrochloride, and deionized water were refluxed to produce the LD-MRP. The NESBM was manufactured by treating SBM with invertase enzyme, followed by heating to induce nonenzymatic browning. Steers were allowed slightly less than ad libitum access to diets fed twice daily and were adapted to their respective treatments within 10 d. On d 11, ruminal and fecal samples were collected at 0, 2, 4, 6, 8, and 12 h after feeding from each of the steers and transported to the laboratory for microbial analysis. Ruminal samples and feces were analyzed for pH and VFA, and both ruminal fluid and feces were tested for acid-resistant E. coli and total coliforms by incubating samples in tryptic soy broth adjusted to pH 2, 4, and 7. Ruminal pH and total VFA concentrations did not differ among treatments. The molar proportion of ruminal acetate was higher (P0.05) for steers receiving NESBM than for steers receiving SBM and LD-MRP. At pH 4, steers that received NESBM had lower (P0.05) ruminal populations of E. coli and total coliforms than steers that received SBM. No differences were observed for ruminal E. coli and total coliforms at pH 2 and 7. Fecal pH was lower (P0.05) for steers fed NESBM than for steers fed SBM or LD-MRP. Molar proportions of fecal acetate were lower (P0.05) and proportions of butyrate and isovalerate were higher (P0.05) for steers fed NESBM compared with steers fed SBM. Fecal E. coli at pH 4 was lower (P0.05) for steers fed NESBM than for steers fed LD-MRP. Fecal E. coli and total coliforms at pH 2 and 7 did not differ among treatments. Dietary MRP had limited effectiveness at decreasing acid-resistant coliforms in the rumen and feces of cattle. Acid resistance in coliforms may depend on protein availability.

One finishing trial and one digestibility trial were used to evaluate wet corn gluten feed (WCGF) and alfalfa hay (AH) combinations in steam-flaked corn (SFC) finishing diets. In Exp. 1, 631 crossbred heifers (initial BW = 284 +/- 7.9 kg) were fed SFC-based diets containing combinations of WCGF (25, 35, or 45% of diet DM) and AH (2 or 6% of dietary DM) in a 2 x 3 factorial arrangement of treatments. No interactions existed between WCGF and AH for heifer performance. Increasing dietary WCGF linearly decreased gain efficiency (P0.01), dietary NEg concentration (P0.05), and 12th-rib fat thickness (P = 0.10). Cattle fed 35% WCGF had the lowest occurrence of abscessed livers, resulting in a quadratic response (P0.05) as dietary WCGF increased. In Exp. 2, 12 ruminally cannulated Jersey steers (585 kg) were fed SFC-based diets containing combinations of WCGF (25 or 45% of diet DM) and AH (0, 2, or 6% of diet DM) in an incomplete Latin square design with a 2 x 3 factorial arrangement of treatments. Starch intake was lower (P0.05), but NDF intake was greater (P0.05) as AH and WCGF increased in the diet. Ruminal pH was increased by AH (linear, P0.05) and tended (P0.07) to increase with WCGF. Feeding 2% AH led to the greatest ruminal NH3 but the lowest total VFA and propionate (quadratic, P0.05). Addition of AH to diets containing 25% WCGF increased acetate to a greater extent than addition to diets containing 45% WCGF (AH x WCGF interaction, P0.05). Feeding 45% WCGF tended to increase passage rate (P = 0.17) and decrease (P0.05) total tract OM digestibility but increase (P0.05) in situ degradation of DM from AH and WCGF. Interactions between AH and WCGF existed (P0.05) for ruminal fluid volume (quadratic effect of AH x WCGF level), in situ SFC degradation (linear effect of AH x WCGF level), and in situ rate of WCGF DM disappearance (quadratic effect of AH x WCGF level). We conclude that AH levels may be decreased when WCGF is added to SFC diets as 25% or more of the dietary DM.

Two experiments were conducted to evaluate the effects of alfalfa hay (AH) and wet corn gluten feed (WCGF) combinations on ADG and gain efficiency of cattle limit-fed growing diets. In Exp. 1, crossbred beef steers (n = 220; initial BW = 262 kg) were limit-fed diets consisting of steam-flaked corn and 40% WCGF (DM basis) with 0, 10, or 20% ground AH (0AH, 10AH, and 20AH, respectively). A fourth diet containing 20% ground AH and steam-flaked corn served as a control. All diets were fed once daily at 1.8% of BW (DM basis). Growing period ADG, gain efficiency, and dietary NE calculated from performance data decreased linearly (P0.01) with addition of AH to diets containing WCGF. Rate of DMI increased linearly (P0.05) with AH addition to diets containing WCGF. Following the growing period, steers were finished on a common diet offered ad libitum. Gain efficiencies during the finishing period were higher (P0.05) for steers fed the 20AH diet than for steers fed the control diet. In Exp. 2, crossbred beef heifers (n = 339; initial BW = 277 kg) were limit-fed diets containing steam-flaked corn with 10, 20, or 30% ground AH and 0, 40, or 68% WCGF in a 3 x 3 factorial arrangement, fed once daily at 1.6% of BW (DM basis). An AH x WCGF interaction occurred (P0.05) for growing period ADG and gain efficiency. Increasing AH or WCGF decreased cattle ADG, gain efficiency, and dietary NE with the exception of heifers fed 30AH/40WCGF, which had ADG that did not differ (P0.10) from that of heifers fed 20AH/0WCGF or 30AH/0WCGF, and which had greater gain efficiencies (P0.05) than heifers fed 30AH/0WCGF. Rate of DMI increased linearly (P0.01) with increasing AH and decreased linearly (P0.01) with increasing WCGF. Heifers were finished on diets containing 33% WCGF with 0 or 0.5% added urea (DM basis) offered ad libitum. Increasing WCGF in growing diets tended (linear, P0.10) to increase finishing ADG and gain efficiency, whereas increasing AH decreased (linear, P0.05) kidney, pelvic, and heart fat, and the percentage of carcasses grading USDA Prime. Urea tended to increase ADG (P0.10), but decreased (P0.04) the percentage of carcasses grading USDA Choice. Results suggest that the value of WCGF relative to steam-flaked corn in limit-fed growing diets might be improved in diets containing 30% AH relative to diets containing 10 or 20% AH.