Evaluation of performance, carcass characteristics, and sensory attributes of beef from finishing steers fed field peas

Whole field peas were fed at 0, 10, 20, and 30% of DM to 139 yearling steers (British cross; 409 ± 31 kg of initial BW) for a 119-d finishing period. Carcass data and Choice grade strip loins (n = 98) were collected from a commercial abattoir in Lexington, Nebraska. Consumer sensory and Warner-Bratzler shear force analyses were performed on 2.5-cm strip steaks. No differences (P ≥ 0.17) were observed in final BW, ADG, DMI, and G:F of steers. Likewise, no differences (P ≥ 0.23) were observed for HCW, LM area, fat thickness at the 12th rib, yield grade, and marbling scores. However, KPH responded quadratically to increasing dietary amount of field peas (P = 0.02). Regarding the sensorial analysis, feeding peas linearly increased subjective tenderness (P < 0.01) and led to a quadratic response of overall like ratings (P = 0.01) and flavor like ratings (P = 0.12). Feeding peas did not alter (P ≥ 0.64) juiciness, but decreased shear force values linearly when quantities were increased (P = 0.02). These data suggest that feeding peas does not affect steer performance or carcass characteristics differently from dry-rolled corn, but does improve objective and subjective tenderness, overall desirability, and flavor of beef. Field peas could be fed to cattle and give positive attributes to the quality of the meat up to 30% inclusion in the diet.

Effects of corn processing method in diets containing sorghum wet distillers grain plus solubles on performance and carcass characteristics of finishing beef cattle and on in vitro fermentation of diets

Two randomized complete block design experiments with a factorial arrangement of treatments were conducted to study the effects of corn processing method and inclusion of sorghum wet distillers grain plus solubles (SWDGS) in beef cattle finishing diets. In Exp. 1, 160 crossbred steers (primarily British x Continental breeding; initial BW = 397.6 +/- 29.4 kg) were fed diets based on dry-rolled (DRC) or steam-flaked corn (SFC), with or without the inclusion of 15% SWDGS (DM basis). Corn processing x SWDGS interactions were not detected (P > or = 0.20) for performance and most carcass characteristics. The G:F was less (P < 0.01) with DRC- than with SFC-based diets. Steers fed SFC-based diets had greater 12th-rib fat thickness (P = 0.03), yield grade (P = 0.02), and a smaller LM area (P = 0.08) than steers fed DRC. Inclusion of 15% SWDGS resulted in decreased G:F (P < 0.01) than for diets without SWDGS. In addition, steers fed SWDGS had decreased HCW (P = 0.01) and dressing percent (P = 0.03) than those fed no SWDGS. In Exp. 2, diet samples from Exp. 1 were used to evaluate rate of in vitro gas production, IVDMD, and H(2)S concentrations in gas. No significant corn processing x SWDGS interactions were noted for any of these measurements or for mathematically fitted gas production parameters, except for the predicted maximum value of gas production. The SFC-based diets had greater IVDMD (P = 0.01), area under the gas production curve (AUC; P = 0.02), and rate (k) of gas production (P = 0.02) than DRC-based diets. Inclusion of 15% SWDGS in the substrates decreased IVDMD (P < 0.01), AUC (P = 0.03), and rate of gas production (P = 0.04) compared with 0% SWDGS. Hydrogen sulfide concentrations in gas did not differ (P > 0.10) with corn processing method or addition of SWDGS. Overall, these data suggest that the response to 15% SWDGS in finishing diets was not affected by corn processing method, but including 15% SWDGS in finishing diets decreased G:F, IVDMD, and gas production AUC values to approximately the same extent as replacing SFC with DRC.

Effect of zilpaterol hydrochloride duration of feeding on performance and carcass characteristics of feedlot cattle

Four trials, each with a randomized complete block design, were conducted with 8,647 beef steers (initial BW = 346 +/- 29.6 kg) in 3 different locations in the United States to evaluate the effects of zilpaterol hydrochloride (ZH) on performance and carcass characteristics of feedlot cattle. Treatments consisted of feeding ZH (8.33 mg/kg of dietary DM) for 0, 20, 30, or 40 d, at the end of the feeding period, followed by a 3-d withdrawal period before slaughter. Cattle were weighed on d 0 and 50 before slaughter (in 3 of the 4 studies), and on the day of slaughter. Data from the 4 trials were pooled for statistical analyses. No differences (P > or = 0.78) were detected among treatments for ADG and G:F from the start of the study until the final 50 d on feed. Final BW was greater for the average of the 3 ZH-treated groups (P < 0.01) than for the 0-d group. Average daily gain was greater for ZH-treated vs. control cattle during the final 50 d on feed (P < 0.01) and for the entire feeding period (P < 0.01). No differences in DMI were noted for any periods of the experiment (P > or = 0.42) for ZH-treated cattle vs. controls. No differences were noted for DMI among the ZH-treated groups for the final 50 d on feed (P = 0.81) or for the overall feeding period (P = 0.31). Feeding ZH for any length of time increased G:F (P < 0.01) for the final 50 d and overall compared with 0-d cattle. In addition, a linear increase with more days of ZH feeding was observed for G:F during the period that ZH was fed (P = 0.01), as well as for the overall feeding period (P = 0.01). The ZH-treated cattle had heavier HCW (P < 0.01), greater dressing percent (P < 0.01), reduced marbling scores (P < 0.01), less 12th-rib fat (P < 0.01), larger LM area (P < 0.01), less KPH (P = 0.01), and a lower USDA yield grade (P < 0.01) than the 0-d cattle, regardless of the duration of ZH feeding. Dressing percent increased linearly (P < 0.01) with increased duration of ZH feeding, whereas 12th-rib fat (P = 0.07), marbling scores (P < 0.01), and USDA calculated yield grade (P = 0.01) decreased linearly with increased duration of ZH feeding. Feeding ZH increased ADG and G:F and decreased overall carcass fatness. In addition, effects of ZH on measures of carcass fatness were enhanced by feeding the product for a greater length of time.

Effects of dietary crude protein and supplemental urea levels on nitrogen and phosphorus utilization by feedlot cattle

Three dietary CP concentrations (11.5, 13.0, and 14.5% of DM) and 3 supplemental urea levels (100, 50, and 0% of supplemental N) were used in a completely randomized block design experiment conducted at 2 locations to determine N and P balance and serum urea N (SUN) concentrations of feedlot cattle. Crossbred steers [British and British x Continental; initial BW = 315.0 +/- 3.2 kg at location 1 (n = 27) and initial BW = 353.2 +/- 8.4 kg at location 2 (n = 27)] were used in 3 nutrient balance sampling periods (SP) at the beginning, middle, and end of the feeding period (154 d in location 1 and 159 d in location 2). Fecal N (g/d; P = 0.03), urinary N (g/d; P < 0.01), urinary urea N (UUN; g/d; P < 0.01), apparent N absorption (g/d; P < 0.01), and SUN concentration (mg/dL; P < 0.01) increased linearly as dietary CP concentration increased. Nitrogen retention (g/d) was not affected (P = 0.61) by dietary CP concentration. Phosphorus intake (g/d; P = 0.02), fecal P (g/d; P = 0.04), and urinary P (g/d; P = 0.01) increased linearly as dietary CP increased, reflecting changes in diet composition with increasing CP concentrations. As dietary urea levels increased, urinary N (g/d; P = 0.04), UUN (g/d; P = 0.01), and apparent N absorption (g/d; P = 0.04) increased linearly, but P intake (g/d; P = 0.10) and urinary P (g/d; P = 0.02) decreased linearly. No interactions were observed between SP and dietary treatments for most variables. Evaluation of SP means, however, showed that as days on feed increased, fecal N (g/d; P = 0.01), urinary N (g/d; P < 0.01), UUN (g/d; P < 0.01), apparent absorption of N (g/d; P < 0.01), SUN (mg/dL; P < 0.01), and urinary P (g/d; P < 0.01) increased linearly, whereas retained N (g/d) decreased linearly (P < 0.01) with increasing days on feed. These data suggest that changes in dietary CP and urea levels, as well as stage of the feeding period, markedly alter N and P utilization by feedlot cattle.

Effects of duration of zilpaterol hydrochloride feeding and days on the finishing diet on feedlot cattle performance and carcass traits

British and British x Continental steers (n = 560; initial BW = 339.4 +/- 1.76 kg) were used in a serial slaughter study with a completely random design to evaluate effects of zilpaterol hydrochloride (ZH; 8.33 mg/kg of dietary DM basis) on performance and carcass characteristics. Treatments were arranged in a 4 x 4 factorial (112 pens; 7 pens/treatment; 5 steers/pen) and included duration of ZH feeding (0, 20, 30, or 40 d before slaughter plus a 3-d ZH withdrawal period) and days on feed (DOF) before slaughter (136, 157, 177, and 198 d). No duration of ZH feeding x slaughter group interactions were detected for the performance measurements (P > 0.10). Final BW did not differ (P = 0.15) between the 0-d group and the average of the 3 ZH groups, but ADG was greater for the average of the 3 ZH groups during the period in which ZH diets were fed (P < 0.01) and for the overall feeding period (P = 0.05). As duration of ZH feeding increased, DMI decreased (P = 0.01) and G:F increased linearly (P < 0.01). With the exception of KPH (P = 0.022), no duration of ZH feeding x slaughter group interactions (P > 0.10) were detected for carcass characteristics. Regardless of the duration of ZH feeding, cattle fed ZH had greater HCW (P < 0.01), greater dressing percent (P < 0.01), less 12th-rib fat (P < 0.01), larger LM area (P < 0.01), less KPH (P = 0.03), and lower yield grade (P < 0.01) than the 0-d cattle. The 0-d group had greater marbling scores (P < 0.01) than cattle fed ZH diets, with a tendency for a linear decrease in marbling score (P = 0.10) as duration of ZH feeding was extended. A greater percentage of carcasses in the 0-d group graded USDA Choice or greater (P < 0.01) than in the 3 ZH groups, whereas the percentage of Select carcasses was greater (P = 0.01) for the 3 ZH groups. From d 0 to end (P = 0.04) and during the last 43 d on feed (P < 0.01), ADG responded quadratically to DOF before slaughter. No differences were detected among slaughter groups for DMI for the entire trial period; however, a quadratic response (P = 0.02) was observed for the final 43 d before slaughter. A quadratic response was also detected for the final 43 d before slaughter (P < 0.01) and from d 0 to end (P = 0.02) for G:F. Final BW, HCW, dressing percent, and 12th-rib fat increased linearly (P < 0.01) as DOF before slaughter increased. Our results indicate that no substantial effects on performance and carcass measurements were observed when ZH was fed for 30 or 40 d as opposed to 20 d, and that effects of ZH generally did not interact with DOF before slaughter.

Effects of increasing dose of live cultures of Lactobacillus acidophilus (Strain NP 51) combined with a single dose of Propionibacterium freudenreichii (Strain NP 24) on performance and carcass characteristics of finishing beef steers

Two experiments, each with a randomized complete block design, were conducted to evaluate the effects of feeding live cultures of Lactobacillus acidophilus plus Propionibacterium freudenreichii on performance and carcass characteristics of feedlot cattle. British and British x Continental steers (240 steers in each experiment; 12 pens/treatment in each study; average initial BW = 370 +/- 6 kg) were fed a 92% concentrate diet based primarily on steam-flaked corn. Four treatments were evaluated, which included a control diet (lactose carrier only) or diets containing 1 x 10(9) cfu/(steer x d) of P. freudenreichii (strain NP 24) with 1 x 10(7) (L), 1 x 10(8) (M), or 1 x 10(9) (H) cfu of L. acidophilus strain NP 51/(steer x d). Data were pooled for the 2 experiments. No differences (P > 0.10) were detected among treatments for final BW, final BW based on HCW, or DMI during various stages of the feeding period or overall. Likewise, no differences among treatments were observed for either ADG or carcass-adjusted ADG (P > 0.10), except for the tendency for a quadratic effect of NP 51 dose for the overall feeding period (P = 0.10), in which cattle fed M had a lower ADG than those fed L and H. Gain efficiency on a live BW basis was improved (P = 0.02) by NP 51 treatments compared with the control, with G:F responding quadratically to NP 51 dose for the overall feeding period (P = 0.05). In contrast to G:F based on live BW, carcass-adjusted G:F tended (P = 0.14) to decrease linearly with increasing NP 51 dose because the dressing percent tended (P = 0.12) to be less for steers fed direct-fed microbial compared with control cattle. Within the direct-fed microbial treatments, there also was a tendency (P = 0.13) for a linear decrease in the dressing percent as the NP 51 dose increased. No differences were observed in other carcass characteristics (P > 0.10), except tendencies for a quadratic increase in marbling score (P = 0.11) and percentage of USDA Choice cattle (P = 0.10). These data indicate that live cultures of L. acidophilus strain NP 51 plus P. freudenreichii strain NP 24 increased G:F of feedlot cattle fed steam-flaked corn-based diets by approximately 2%, but the effects depended on the dose of Lactobacillus.

Effects of ractopamine hydrochloride on performance, rate and variation in feed intake, and acid-base balance in feedlot cattle1

Two experiments evaluated effects of ractopamine hydrochloride (RAC) on performance, intake patterns, and acid-base balance of feedlot cattle. In Exp. 1, 360 crossbred steers (Brangus, British, and British x Continental breeding; initial BW = 545 kg) were used in a study with a 3 x 3 factorial design to study the effects of dose [0, 100, or 200 mg/(steer x d) of RAC] and duration (28, 35, or 42 d) of feeding of RAC in a randomized complete block design (9 treatments, 8 pens/treatment). No dose x duration interactions were detected (P > 0.10). As RAC dose increased, final BW (FBW; P = 0.01), ADG (P < 0.01), and G:F (P < 0.01) increased linearly. As duration of feeding increased, ADG increased quadratically (P = 0.04), with tendencies for quadratic effects for FBW (P = 0.06), DMI (P = 0.07), and G:F (P = 0.09). Hot carcass weight increased linearly (P = 0.02) as dose of RAC increased. Thus, increasing the dose of RAC from 0 to 200 mg/(steer x d) and the duration of feeding from 28 to 42 d improved feedlot performance, although quadratic responses for duration of feeding indicated little improvement as the duration was extended from 35 to 42 d. In Exp. 2, 12 crossbred beef steers (BW = 593 kg) were used in a completely random design to evaluate the effects of RAC [0 or 200 mg/(steer x d) for 30 d; 6 steers/treatment] on rate of intake, daily variation in intake patterns, and acid-base balance. To assess intake patterns, absolute values of daily deviations in feed delivered to each steer relative to the total quantity of feed delivered were analyzed as repeated measures. There were no differences (P > 0.10) in feedlot performance, urine pH, blood gas measurements, or variation in intake patterns between RAC and control cattle, but steers fed RAC had increased (P = 0.04) LM area, decreased (P = 0.03) yield grade, and increased (P < 0.10) time to consume 50 and 75% of daily intake relative to control steers. Our results suggest that feeding RAC for 35 d at 200 mg/(steer x d) provided optimal performance, and no effects on acid-base balance or variation in intake patterns of finishing steers were noted with RAC fed at 200 mg/(steer x d) over a 30-d period.

Effects of wet corn gluten feed and roughage levels on performance, carcass characteristics, and feeding behavior of feedlot cattle1

Two experiments were conducted to evaluate the effects of feeding different levels of wet corn gluten feed (WCGF) and dietary roughage on performance, carcass characteristics, and feeding behavior of feedlot cattle fed diets based on steam-flaked corn (SFC). In Exp. 1, crossbred steers (n = 200; BW = 314 kg) were fed 4 dietary treatments (DM basis): a standard SFC-based diet containing 9% roughage (CON) and 3 SFC-based diets containing 40% WCGF, with either 9, 4.5, or 0% roughage. A linear (P = 0.04) increase in final BW and DMI (P < 0.01) was observed in diets containing WCGF as dietary roughage increased. Steers fed WCGF and higher levels of roughage had greater (P = 0.01) ADG than steers fed lower levels of roughage. Steers fed the CON diet had lower (P = 0.04) daily DMI and greater (P = 0.03) G:F than those fed WCGF. Most carcass characteristics of steers fed CON did not differ (P > 0.10) from those of steers fed WCGF. Based on feed disappearance and visual scan data, consumption rate did not differ (P > 0.10) among treatments; however, feeding intensity (animals present at the bunk after feeding) was greater for steers fed CON (P < 0.01) than for steers fed WCGF. In Exp. 2, yearling crossbred steers (n = 1,983; BW = 339 kg) were fed 4 dietary treatments (DM basis): a standard SFC-based control diet that contained 9% roughage (CON) and 3 SFC-based diets containing either 20% WCGF and 9% roughage or 40% WCGF with 9 or 4.5% roughage. Steers fed the CON diet tended to have lower final BW (P = 0.14), ADG (P = 0.01), and DMI (P < 0.01) than steers fed diets containing WCGF. Steers fed the 20% WCGF diet had greater (P = 0.08) G:F than steers fed the 40% WCGF diets. With 40% WCGF, increasing roughage from 4.5 to 9% decreased (P < 0.01) G:F and increased (P = 0.06) DMI. Gain efficiency was improved (P < 0.01) for steers fed CON vs. those fed diets containing WCGF, whereas HCW (P = 0.02) and dressing percentage (P < 0.01) were greater for steers fed WCGF. Percentage of cattle grading USDA Choice was greater (P = 0.02) for cattle fed WCGF. Results suggest that replacing SFC with up to 40% WCGF increased ADG and decreased G:F when 4.5 to 9.0% roughage was supplied. More CON steers were present at the feed bunk during the first hour after feeding than WCGF steers, suggesting that including WCGF at 40% of the diet affected feeding behavior.

Effects of source of supplemental zinc on performance and humoral immunity in beef heifers1

Two experiments were conducted to evaluate receiving-period performance, morbidity, and humoral immune response, as well as finishing performance and carcass characteristics of heifers fed different sources of supplemental Zn. In Exp. 1, 97 crossbred beef heifers (initial BW = 223.4 kg) were fed a 65% concentrate diet with no supplemental Zn (control) or 75 mg of supplemental Zn/kg of DM from Zn sulfate, Zn methionine, or Zn propionate. During a 35-d receiving period, heifers were monitored daily for signs of bovine respiratory disease. Serum samples were collected for Zn analysis on d 0, 14, and 28. After the receiving period, heifers were adapted to and fed a high-concentrate diet with no supplemental Zn for 42 d. Heifers were then assigned to finishing diet treatments, with the same concentrations and sources of supplemental Zn as during the receiving period and fed for an average of 168 d. Serum samples also were obtained on d 0 and 56 of the finishing period and at the end of the study. During the receiving period, control heifers had a greater (P < or = 0.05) BW and G:F on d 35 than heifers in the other treatments, but no differences were observed among treatments for morbidity or serum Zn concentrations (P > or = 0.50). For the finishing period, DMI and ADG did not differ among treatments; however, overall G:F tended (P = 0.06) to be less for control heifers than for heifers in the 3 supplemental Zn treatments. On d 56 of the finishing period, control heifers tended (P = 0.06) to have a lower serum Zn concentration than heifers in the 3 supplemental Zn treatments. In Exp. 2, 24 crossbred beef heifers (initial BW = 291.1 kg) were fed the same 4 treatments as in Exp. 1 for a 21-d period. The humoral immune response to treatments was determined by measuring specific antibody titers after s.c. injection of ovalbumin on d 0 and 14. Body weights and blood samples for serum Zn concentration and ovalbumin IgG titers were collected on d 0, 7, 14, and 21. Serum Zn concentration and specific ovalbumin IgG titers did not differ (P > 0.10) among the 4 treatments on any sampling day. Results from these 2 studies showed no major differences among the sources of supplemental Zn for receiving period morbidity, ADG, DMI, and humoral immune response of beef heifers; however, a lack of supplemental Zn during an extended finishing period tended to negatively affect G:F.

Nutritional recommendations of feedlot consulting nutritionists: the 2007 Texas Tech University survey

Forty-two consulting feedlot nutritionists were asked to participate in a survey regarding nutritional recommendations for feedlot cattle. Eleven nutritionists chose not to participate or did not reply to our request. Thirty-one nutritionists agreed to participate, and 29 completed the survey. Their practices were located in the following states: Texas, Kansas, and Oklahoma (46.43%); Iowa, Nebraska, Colorado, and South Dakota (31.25%); Washington and Idaho (8.93%); Arizona and California (6.25%); and other states (7.14%). The survey was conducted using a Web-based system and included 74 questions divided into sections that covered general information about the nutritionist's practice (n = 8 questions); commodity information (n = 13); use of grain coproducts (n = 5); information regarding roughage sources and levels (n = 4); methods used to adapt cattle to finishing diets (n = 3); information about supplements and micronutrients (n = 7); types of feed mixers (n = 2) and feed mills (n = 1) used by clients; feeding (n = 1) and cattle management (n = 5); liquid feeds (n = 7); recommendations for nutrient formulation (n = 15); information resources used as the basis for nutritional recommendations (n = 2); and perceived needs for additional information on items or nutrients not addressed in the survey. With respect to nutrient formulation practices, the results indicated that the recommended concentrations of major nutrients and trace minerals typically fell within a range of 1 to 2 times the NRC (2000) recommendations for beef cattle; however, some important aspects of the NRC models (e.g., formulation for degradable intake protein) were not applied by the majority of respondents. Data from this survey provide a snapshot of practices used by feedlot nutritionists and should aid in development of future National Research Council models and recommendations.

Effects of phase feeding of protein on performance, blood urea nitrogen concentration, manure nitrogen:phosphorus ratio, and carcass characteristics of feedlot cattle

Two experiments with a randomized complete block design were conducted to determine the effects of phase feeding of CP on performance, blood urea nitrogen (BUN), manure N:P ratio, and carcass characteristics of steers fed in a feedlot. In Exp. 1, 45 crossbred steers (initial BW = 423 +/- 3.3 kg) were individually fed a diet formulated to contain 13.0% CP (DM basis) for 62 d. On d 63, the dietary CP was maintained at 13.0% or formulated to contain 11.5 or 10.0% CP until slaughter. Actual CP values were 12.8, 11.8, and 9.9%, respectively. Reducing the CP concentration of the diet did not affect ADG of steers from d 62 to 109 (P = 0.54) or over the 109-d feeding period (1.45, 1.50, and 1.49 kg/d for 13.0, 11.5, and 10.0% CP, respectively; P = 0.85). No differences (P > 0.12) among treatments were detected for BUN concentrations on d 0, 62, or 109. Gain:feed, DMI, and carcass characteristics did not differ among treatments (P > 0.10). In Exp. 2, 2 trials were conducted using 184 (initial BW = 406 +/- 2.6 kg) and 162 (initial BW = 342 +/- 1.9 kg) crossbred steers. Data from the 2 trials were pooled for statistical analysis, and trial effect was added to the statistical model. Steers were fed a diet formulated to contain 13.0% CP until reaching approximately 477 kg. When the average BW of the pen was 477 kg, diets were maintained at 13.0% CP or reduced to contain 11.5 or 10.0% CP. Actual CP values were 12.4, 11.5, and 9.3% CP for treatments 13.0, 11.5, and 10.0% CP, respectively. Reducing the CP content of the diet did not affect ADG after the diet changed (P = 0.16) or throughout the finishing period (P = 0.14). Immediately before slaughter, steers fed the 13.0% CP diet had greater (P < 0.001) BUN concentrations than steers fed the 11.5 and 10.0% CP diets. Carcasses from cattle fed the 11.5% CP diet had greater (P = 0.02) fat thickness than the 13.0 and 10.0% CP treatments, whereas carcasses from cattle fed 13.0% CP had greater (P = 0.004) marbling scores than steers fed the 11.5 or 10.0% CP diets. Other carcass characteristics, DMI, and G:F did not differ (P > 0.10) among treatments. The N:P ratio was increased with the 10.0% CP diet (P = 0.02) compared with the 11.5 or 13.5% CP treatments; however, manure composition did not differ (P > 0.10) among treatments. These results indicate that reduced CP concentration during the finishing period does not affect feedlot performance but can improve the N and P relationship in the manure.

[Acquired ventricular septal defect during infective endocarditis]

We studied five patients with acquired ventricular septal defect during the course of an infective endocarditis. All patients were male and had a previous aortic valve disease associated with an aortic ring abscess. Clinical examination was useful for the diagnosis of 4 cases, emphasizing the following findings: systolic murmur and/or left paraesternal thrill and right-heart failure. Incidence of congestive heart failure was 60%, while 40% of all patients died during the in-hospital course. No specific etiologic agent was detected. Therefore, acquired ventricular septal defect should be suspected in patients with infective endocarditis of the aortic valve that evolve with a systolic murmur and/or paraesternal thrill and right-heart failure. Immediate surgical treatment is mandatory in these cases.