Marcelo Henrique de Faria

Immunocastration improves carcass traits and beef color attributes in Nellore and Nellore×Aberdeen Angus crossbred animals finished in feedlot.

The objective was to examine the effects of immunocastration on carcass traits and meat quality of Nellore and Nellore×Aberdeen Angus male animals finished in feedlot. Surgically castrated, immunocastrated, and intact animals were finished in feedlot for 90 days. The animals were harvested, and carcass traits were evaluated. Carcasses were chilled, and one 2.5-cm steak was fabricated from Longissimus thoracis muscle. The steaks were individually vacuum packaged and frozen at -18 °C. Frozen steaks were thawed, and pH, instrumental color, cooking loss, and shear force were determined. Immunocastrated animals demonstrated greater (P<0.05) hot dressing percentage and cold dressing percentage than their surgically castrated counterparts. Furthermore, steaks from immunocastrated and surgically castrated animals exhibited greater redness (P<0.05) and lower darkness (P<0.05) than steaks from intact animals, indicating possible advantage in retailing. The results suggested that immunocastration may be utilized to improve carcass traits and beef color in feedlot-finished Nellore and Nellore×Aberdeen Angus males.

Animal performance and carcass characteristics of Nellore young bulls fed coated or uncoated urea slaughtered at different weights

The objective of this study was to evaluate animal performance and carcass characteristics of 64 Nellore young bulls at 22 months of age finished in a feedlot and slaughtered at five body weights (350; 455; 485; 555 and 580 kg) fed diets containing coated or uncoated urea. The experimental design adopted was completely randomized, set in a 4 × 2 factorial arrangement, and for the variables assessed in the control animals, it was 5 × 2. No effect of interaction between slaughter weights and diets were observed, so the variables were analyzed separately, compared by polynomial contrasts and by the F test, respectively. The time animals remained in the feedlot to reach slaughter weights was 66, 88, 145 and 194 days. Average daily gain (ADG) showed quadratic behavior, with a maximum of 1.44 kg/day with animals of 491.7 kg. Dry matter intake (DMI) (kg/day) was similar in all the treatments, but it decreased linearly as body weight increased. The bionutritional efficiency worsened linearly as body weight rose. The elevation in slaughter weight resulted in linear decrease in the percentage of beef round and increase in forequarter. Backfat thickness and rib eye area of the longissimus increased linearly and the percentages of muscle and protein in the carcass reduced and those of fat and ether extract increased linearly as body weight increased. Average daily gain, DMI, feed efficiency and carcass characteristics were not affected by diets containing coated or uncoated urea. However, animals fed coated urea presenter better crude fiber and neutral detergent fiber intake.

Performance of finishing beef cattle fed different diets containing whole-crop maize silage or sugarcane silage

Objetivou-se com este trabalho avaliar o desempenho de bovinos de corte em confinamento alimentados com racoes contendo silagem de milho ou de cana-de-acucar, e com diferentes formulacoes. Foram avaliadas cinco racoes: SMF - racao contendo silagem de milho, com formulacao fixa durante o periodo de confinamento; SMV - racao contendo silagem de milho, com formulacao variavel conforme a fase de confinamento; SCF: racao contendo silagem de cana-de-acucar, com formulacao fixa; SCV: racao contendo silagem de cana-de-acucar, com formulacao variavel; SCV/SMV: SCV na metade inicial do confinamento e SMV na metade final. O delineamento experimental foi o inteiramente casualizado, com cinco tratamentos e tres repeticoes (baias). Foram utilizados 285 bovinos castrados, com idade de 36 meses e peso vivo inicial de 362,4 kg. As racoes contendo silagem de milho promoveram maior consumo de materia seca (10,5 kg e 2,4% PV) em comparacao aquelas contendo silagem de cana-de-acucar (10,1 kg e 2,3% PV). Nao houve efeito das silagens sobre o ganho medio diario (1,348 kg/animal/dia) e peso vivo ao abate (481,2 kg PV). A racao SCV/SMV promoveu a pior conversao alimentar (8,0 kg MS/kg PV). Os animais alimentados com as racoes compostas com silagem de milho apresentaram maior peso de carcaca quente, rendimento de carcaca e espessura de gordura subcutânea (262,1 kg, 54,1% e 6,2 mm) em relacao aqueles que receberam a silagem de cana-de-acucar (252,5 kg, 52,7% e 4,8 mm). A utilizacao de silagem de cana-de-acucar em racoes para bovinos de corte em terminacao e viavel e o ajuste da formulacao durante o periodo de confinamento nao influencia o desempenho dos animais. A troca de silagem de cana-de-acucar por silagem de milho durante o periodo de alimentacao interfere negativamente na conversao alimentar.

Beef quality of young Angus × Nellore cattle supplemented with rumen-protected lipids during rearing and fatting periods

This work evaluated the beef quality parameters of 108 bulls randomly administered to three treatments during rearing in pastures and two treatments during fatting in feedlots, including mineral and rumen-protected lipids. Meat and fat color, cooking yield, shear force, sensorial traits and chemical and fatty acid compositions were evaluated. Generally, the beef quality parameters were not affected by the rumen protected lipids; however, supplementation with rumen-protected lipids during the rearing period yielded darker beef and brighter fat and increased beef tenderness in meat aged for 28days compared to the meat from animals that received only mineral supplementation. In addition, the percent of meat polyunsaturated fatty acids was negatively affected by the inclusion of protected lipids, yielding 5.58 and 3.72% in animals fed with and without rumen-protected lipids, respectively, during the fatting period.

Carcass characteristics of feedlot-finished Zebu and Caracu cattle

This study analyzes the chemical carcass characteristics and carcass losses in 86 cattle, both castrated and non-castrated, with an average initial weight of 329 kg and an average age of approximately 20 months, including 12 Gyr, 20 Guzerat, 20 Nellore, and 20 Caracu among the herds selected for weight determination at 378 days of age, as well as 14 Nellore cattle that were not selected. The diet contained a roughage-to-concentrate ratio of 60:40 in terms of dry matter (DM), with 14.8% crude protein as a percentage of DM and corn silage as roughage. A completely randomized 5 × 2 factorial experimental design was used, including five breeds and two sex classes. The following values were determined: losses due to the trimming of commercial cuts and cooking; shear force; the temperature and pH of the meat; and the chemical composition of the Hankins and Howe section (HH section). The castrated animals exhibited greater losses from the front trimmings compared with the non-castrated cattle. There were no differences in the final pH values of the carcasses among the breeds, although the noncastrated animals exhibited higher values than the castrated ones, likely because non-castrated animals were more susceptible to stress. The final pH remained within the range considered optimal for all of the carcasses studied. No differences were observed in the shear force among the breeds or between the two sexes. When appropriately managed, zebu breeds are capable of producing tender meat, thus meeting the demands of the consumer market.

Performance and carcass quality of feedlot- or pasture-finished Nellore heifers according to feeding managements in the postweaning phase

The objective of this study was to evaluate the postweaning history of heifers kept on marandu grass pastures with three canopy heights, in a continuous-grazing system, during the rainy period, on feedlot- or pasture finishing. The effects of three canopy heights (15, 25 and 35 cm) associated with two supplements (mineral salt and protein-energy supplement) and two finishing systems in the dry period (feedlot and open pasture) were studied in the postweaning period during the rainy season. The adopted design was completely randomized, with seven replications (animals) in a 2 × 2 factorial arrangement. The animals which received protein-energy supplement reached the finishing period with greater body weight in relation to those fed mineral salt. In both feedlot and pasture finishing systems, compensatory gain effect was observed in the animals that remained on the low pastures during postweaning compared with the high pastures. This compensatory gain was not verified in the animals that received protein-energy supplement in relation to the mineral salt, and thus the animals were slaughtered beforehand. The heifers on pastures with 25 or 35 cm in height were slaughtered in the same period, and those kept on the low pastures were slaughtered afterwards. The studied factors in the postweaning phase did not affect the carcass characteristics. Animals finished in feedlot slaughtered with the same body weight as those finished on pasture show greater carcass yield, subcutaneous fat deposition and renal pelvic and inguinal fat and greater losses with trimmings for cleaning the main hindquarter meat cuts; however, they provide cuts with the same weight but greater fat cover.

Performance and carcass characteristics of beef cattle fed with ammoniated marandugrass hay

Objetivou-se avaliar o efeito da inclusao da amonia anidra ou ureia em fenos de residuo pos-colheita de sementes de Brachiaria brizantha e da fonte proteica suplementar ao feno nao-tratado sobre o desempenho e as caracteristicas de carcaca de bovinos confinados. Vinte e quatro animais nao-castrados (12 animais F1 Nelore Aberdeen Angus, variedade preta, e 12 F1 Nelore Aberdeen Angus, variedade vermelha) foram distribuidos aleatoriamente em quatro tratamentos, totalizando seis repeticoes, considerando blocos o cruzamento e o peso inicial. As dietas experimentais consistiram de feno nao-tratado suplementado com nitrogenio nao-proteico; feno nao-tratado suplementado com farelo de algodao; feno tratado com 5% de ureia; e feno tratado com 3% de amonia anidra (% MS). Os valores de peso vivo inicial, consumo diario e consumo relativo de MS nao diferiram entre as dietas e apresentaram medias de 422,6 kg, 9,80 kg e 2,1%, respectivamente. O ganho medio diario (GMD) e a conversao alimentar apresentaram diferencas que evidenciaram melhor desempenho dos animais alimentados com o feno tratado com amonia, cujos valores foram de 1,336 kg/dia e 7,78 kg de MS ingerida/kg de GMD, seguidos daqueles alimentados com o feno nao-tratado e suplementado com farelo de algodao, de 1,161 kg/dia e 8,98 kg de MS ingerida/kg de GMD, respectivamente. Os consumos de nutrientes diferiram, resultando em maiores consumos de fibra em detergente neutro (FDN), fibra em detergente acido (FDA) e celulose pelos animais alimentados com feno tratado com amonia. Os maiores valores de espessura de gordura subcutânea foram obtidos com a dieta com feno tratado com amonia (6,3 mm).