Judson Vasconcelos

A snapshot of management practices and nutritional recommendations used by feedlot nutritionists in Brazil.

Feedlot consulting nutritionists were invited to participate in a survey of feedlot nutritional and management practices in Brazil. Thirty-one nutritionists completed the survey on a Web site that was designed for collection of survey data. The survey consisted of 94 questions that included general information (n = 10); commodity information (n = 12); and questions about the use of coproducts (n = 5), roughage source and levels (n = 5), finishing diet adaptation methods (n = 7), supplements and micronutrients (n = 8), feed mixers (n = 6), feeding management (n = 3), cattle management and type of cattle fed (n = 16), formulation practices (n = 17), information resources used for nutritional recommendations (n = 2), and 2 additional questions. One final question addressed the primary challenges associated with applying nutritional recommendations in practice. The number of animals serviced yearly by each nutritionist averaged 121,682 (minimum = 2,000; maximum = 1,500,000; mode = 120,000; total = 3,163,750). Twenty-two respondents (71%) worked with feedlots that feed less than 5,000 animals/yr. Labor, along with availability and precision of equipment, seemed to be the main challenges for the nutritionists surveyed. Most of the nutritionists surveyed used TDN as the primary energy unit for formulation. More than 50% of the clients serviced by the 31 nutritionists did not manage feed bunks to control the quantity of feed offered per pen, and 36.6% fed cattle more than 4 times daily. The NRC (1996) and Journal of Animal Science were the most used sources of information by these nutritionists. Overall, general practices and nutritional recommendations provided by the 31 nutritionists surveyed were fairly consistent. Present data should aid in development of new research, future National Research Council models, and recommendations for Brazilian feeding systems in which Bos indicus cattle predominate.

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.

Effect of sulfur content in wet or dry distillers grains fed at several inclusions on cattle growth performance, ruminal parameters, and hydrogen sulfide

Effects of S from wet or dry distillers grains with solubles (DGS) containing 0.82 or 1.16% S on animal growth performance, carcass characteristics, apparent total tract digestibility, and ruminal parameters were evaluated. In Exp. 1, crossbred beef steers (n = 120; 345 ± 34 kg BW) were individually fed ad libitum using Calan gates. Treatments were applied as a 2 × 2 × 3 + 1 factorial treatment arrangement with factors of DGS type (wet or dry), S content in DGS (0.82 or 1.16% DM basis), and DGS inclusion (20, 30, and 40%, DM basis), as well as a corn control diet (no DGS). In Exp. 2, ruminally cannulated crossbred beef steers (n = 6; 381 ± 31 kg BW) were assigned to 1 of 5 diets in a 5 × 6 unbalanced Latin Square design and fed ad libitum through five 14-d periods. A 2 × 2 + 1 factorial treatment arrangement was used with the factors of DGS type and S content in DGS (similar to Exp. 1). Inclusion of DGS was 40%, except for a MATCH diet containing wet 1.16% S DGS included at 31.4% (DM basis). Intake of DM decreased linearly (P < 0.01) and quadratically (P < 0.01) for steers fed wet and dry DGS that was 1.16% S, respectively. In addition, steers fed dry DGS consumed 9% more DM (P < 0.01) than those fed wet. Gain decreased linearly (P = 0.02) when wet 1.16% S DGS increased in the diet, representing a 12% drop in ADG between the Control and 40% DGS inclusion. A quadratic (P = 0.02) improvement in G:F was observed for steers fed wet DGS compared with dry, regardless of S content (P = 0.52). Feeding diets with wet 1.16% S DGS linearly decreased (P = 0.03) HCW. In Exp. 2, molar proportion of propionate declined (P = 0.01) 9% and A:P ratio tended (P = 0.13) to be greater when 1.16 compared with 0.82% S DGS was fed. Apparent total tract DMD was not affected (P > 0.16) and only subtle changes (P < 0.01) in ruminal pH parameters were observed. Greater (P = 0.02) ruminal H2S concentration for steers fed wet compared with dry DGS was observed, while 1.16% S DGS tended (P = 0.12) to produce greater ruminal H2S than 0.82% S. Sulfur in wet DGS appears to be more prone to be converted to ruminal H2S, because feeding 1.16% S as wet DGS had a greater impact on ADG, DMI, and ruminal H2S compared with dry DGS.

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.

Evaluation of Revalor-IH and Revalor-IS as Initial Implants Compared with Traditional Initial Implants for Finishing Heifers and Steers

Two commercial feedlot experiments were conducted to compare performance and carcass characteristics of feedlot heifers and steers using 2 implant strategies. In Exp. 1, heifers (n = 1,124;

Comparison of Revalor XS, a new single-dose implant, to a Revalor IS and Revalor S implant strategy in finishing steers1

ABSTRACT A commercial feedlot study compared effects of a Revalor IS/Revalor S implant program to a Revalor XS single-implant program on performance and carcass characteristics of feedlot cattle. Yearling crossbred steers (1,356; BW = 313.3 ± 16.0 kg) were used in a randomized complete block designed trial. Pens were assigned randomly to 1 of 2 implant treatments. Cattle on the Revalor IS/Revalor S treatment were reimplanted on d 80 with Revalor S. Diets consisted of 54.9% dry-rolled corn, 35% wet distillers grains plus solubles, 5.5% mixed hay, and 4.6% liquid supplement (DM basis). There were no differences (P = 0.96) in DMI because of treatment. Also, no differences (P > 0.90) in final BW, ADG, or G:F were observed on a carcass-adjusted basis. No differences in final BW, ADG, and G:F (P > 0.50) were observed for live performance. Marbling score, 12th-rib fat thickness, LM area, and YG were unaffected (P > 0.69) by implant strategies. Steers on the Revalor XS treatment had a greater number of Low Choice carcasses (P = 0.01) and a lower number of Select carcasses (P = 0.02) compared with Revalor IS/Revalor S, with 58% of Revalor XS cattle grading Low Choice and 50% of Revalor IS/Revalor S cattle grading Low Choice. Steers on the Revalor XS treatment tended to have a greater (P = 0.11) number of USDA YG 5 carcasses. Steers implanted with Revalor XS performed similar to cattle implanted initially with Revalor IS followed by Revalor S.

Effect of degradable intake protein supplementation in finishing diets containing dried distillers grains or wet distillers grains plus solubles on performance and carcass characteristics1

ABSTRACT Two finishing trials were conducted to determine whether supplemental degradable intake protein is necessary to optimize performance in dry-rolled corn (DRC) based finishing diets containing distillers grains. Diets without urea were deficient in degradable intake protein based on the NRC (1996) recommendations, yet all diets had positive metabolizable protein balances. In Exp. 1, individually fed, crossbred heifers (n = 58; BW = 383 ± 25 kg) were used in a completely randomized design with a 2 × 2 factorial arrangement of treatments. Dietary treatments contained 10 or 20% dried distillers grains replacing DRC, with or without 0.80 or 0.63% urea, respectively (DM basis). Blood samples were analyzed for BUN. Heifers receiving urea or 20% dried distillers grains (P 0.10) were observed for performance or carcass characteristics for either experiment. These data indicate supply of ruminal degradable intake protein was adequate to maintain performance when at least 10% distillers grains was included in DRC diets.

Effect of Feeding Melengestrol Acetate, Monensin, and Tylosin on Performance, Carcass Measurements, and Liver Abscesses of Feedlot Heifers

Approximately 4,000 yearling heifers (initial BW = 306 ± 1.9 kg) were randomly allotted into 4 treatment groups to determine the effect of melengestrol acetate (MGA) on feedlot performance and carcass parameters. Treatments included a diet containing monensin (Rumensin) and tylosin (Tylan; RT) fed during the entire feeding period; RT plus MGA (RTM) also fed during the entire feeding period; RT withdrawn 35 d preslaughter (RTwd); and RTM withdrawn 35 d preslaughter (RTMwd). All cattle were implanted at arrival with Revalor-IH and reimplanted with Revalor-200, and were fed a standard feedlot finishing diet (that met or exceeded 1996 NRC requirements) for approximately 150 d. Final BW, ADG, hot carcass weight (HCW), DMI, and percentage of cattle grading Choice were greater (P < 0.05) for RTM than for all other treatments. Withdrawal of MGA (RTMwd) significantly (P < 0.01) decreased ADG, HCW, 12th-rib fat thickness, calculated YG, and percentage of carcasses grading Choice, but significantly increased the percentage of dark-cutting carcasses, LM area, and YG 1, 2, or 3 carcasses compared with RTM. There were no significant differences (except for dressing percentage) between RT and RTwd. Heifers continuously fed MGA increased in ADG, HCW, and carcass quality traits of economic importance compared with other treatments. Withdrawal of MGA, Rumensin, and Tylan 35 d preslaughter adversely affected carcass weight and carcass quality traits of economic importance when compared with a feeding program including MGA, Rumensin, and Tylan.

A Comparison of Melengestrol Acetate Fed at Two Dose Levels to Feedlot Heifers

A randomized complete block design was used to compare the effects of feeding melengestrol acetate (MGA) at 0.4 (0.4M) and 0.5 (0.5M) mg/d per head on feedlot performance, estrus activity, and carcass characteristics of commercial beef heifers (n = 1,418; 10 pens/ treatment). Within 48 h of arrival at the research site, heifers were assigned to treatment, processed according to feedlot protocol, and administered an abortifacient. After adaptation to a 95% concentrate diet, MGA was supplied at either 0.4 or 0.5 mg/head daily. Estrus activity was monitored twice daily and summarized as a count of heifers showing estrus within a pen over each 21-d interval throughout the study. Dry matter intake, ADG, G:F, and all other carcass measurements were not different (P > 0.10) between treatments. Overall treatment effects were different only for estrus activity (P = 0.03; 3.2 vs. 2.1% for 0.4M and 0.5M, respectively) and tended to be different for the percentage of dark-cutting carcasses (P = 0.10; 3.0 vs. 1.7% for 0.4M and 0.5M, respectively). Results of this study showed little difference between treatment groups for performance and carcass characteristics of feedlot heifers. The decrease in estrus activity and percentage of dark-cutting carcasses, however, may suggest an economic advantage of feeding a higher level of MGA to finishing heifers.