In this article we research the influence of different sources of carbohydrates (corn, soybean hulls or wheat bran) upon the digestive behavior of 24 confined castrated steers with an initial average age and weight of 20 months and 330 kg born from the cross between Charolais and Nellore. The diet was composed of 40% sorghum silage and 60% concentrate. The time spent on total ruminating (an average of 454.6 min/day) was not influenced by the source of carbohydrate. The animals from the wheat bran treatment spent less time idle (718 min) in relation to those on the corn and soybean hulls treatments, which did not differ between themselves (an average of 792 min/day). The steers from the wheat bran treatment remained less time feeding (184 min/day) compared with those fed the other treatments, whose average time of permanence in this activity was 214 minutes per day. The other studied variables did not present a significant difference between the treatments. Inclusion of wheat bran in the diet of the confined steers results in less spent time idle, while steers feeding on soybean hulls spend less time feeding. The use of corn, soybean hulls, or wheat bran in the diet of the confined steers does not affect the total cudding time.

O objetivo deste trabalho foi avaliar o perfil lipídico da carne de novilhos Devon, terminados em pastagem de milheto (Pennisetum americanum) e alimentados com dieta suplementar de um concentrado a diferentes taxas. Doze animais, com 270 kg e idade média inicial de 12 meses, foram distribuídos ao acaso, em três tratamentos: pastagem de milheto; pastagem de milheto e suplemento concentrado a 0,5 ou 1,0% do peso corporal, com duas repetições. Os teores totais de ácidos graxos saturados e insaturados, a relação poli‑insaturados:saturados e outros ácidos relevantes como o vacênico, o linoleico conjugado, o ômega‑3 e ômega‑6 não foram influenciados pelo consumo de suplemento concentrado a 0,5 ou 1,0% do peso vivo. Entretanto, a suplementação a 0,5% reduziu a concentração do ácido graxo dihomo‑γ‑linolênico (C20:3 n‑6), enquanto a suplementação a 1,0% elevou o teor do ácido graxo docosahexaenoico (DHA) (C22:6 n‑3) e a relação ômega‑6:omega‑3 na carne. O consumo de até 1,0% de suplemento energético aumenta a relação ômega‑6:ômega‑3 na carne de novilhos Devon mantidos em pastagem de milheto.

The objective of this work was to evaluate the meat lipid profile from Devon beef steers finished in pearl millet (Pennisetum americanum) pasture and fed at different rates of concentrate supplementary diet. Twelve steers weighing 270 kg, at 12‑month‑average initial age, were randomly distributed into three treatments: pearl millet pasture; and pearl millet pasture plus a concentrate equivalent at 0.5 or 1.0% of body weight, with two replicates. Total contents of saturated and unsaturated fatty acids, the polyunsaturated:saturated ratio and other relevant fatty acids as the vaccenic acid, conjugated linoleic acid, omega‑3, and omega‑6 were not affected by the consumption of a concentrate supplement at 0.5 or 1.0% live weight. However, the 0.5% supplementation level reduced the concentration of dihomo‑γ‑linolenic fatty acid (C20: 3 n‑6), while the 1.0% supplementation level elevated the content of docosahexaenoic (DHA) (C22: 6 n‑3) fatty acid, and the omega‑6:omega‑3 ratio in meat. Consumption of up to 1.0% energy supplementation increases the omega‑6:omega‑3 ratio in meat from Devon steers grazing on pearl millet pasture.

The objective of this study was to evaluate the effect of carbohydrate sources (corn, soybean hulls or wheat bran) in the diet on performance of feedlot steers in the finishing phase. Twenty-four Charolais × Nellore crossbred steers, aged 22 months and initial weight of 335.0±10.9 kg were used in the experiment. Diets contained 40% sorghum silage and 60% concentrate. The intakes of dry matter (DM; 10.68, 10.16 and 10.34 kg/day) and crude protein (1.66, 1.70 and 1.72 kg/day) were not affected by diets with corn, soybean hulls or wheat bran, respectively. The intakes of neutral and acid detergent fiber were higher for soybean hulls, but the diet containing corn provided higher intake of non-fibrous carbohydrates, total digestible nutrients and digestible energy. Weight gain was higher and better feed conversion for animals fed corn (1.57 kg/day, 6.85 kg DM/kg gain) or soybean hulls (1.58 kg/day and 6.61 kg DM/kg gain) compared with steers receiving wheat bran (1.29 kg/day and 8.14 kg DM/kg gain) in the diet. There was no significant effect of carbohydrate sources on the final body score (3.78 points), energy conversion (28.25 Mcal digestible energy/kg gain), hot carcass yield (57.63 kg/100 kg BW) and fat thickness (3.1 mm). From an economic point of view, soybean hulls can be an alternative source of carbohydrate to corn in diets of finishing steers with 60% concentrate.

The response of energy supplementation was evaluated on the development and reproductive performance of beef heifers on temperate grasslands. Twenty-eight Charolais × Nellore heifers, with initial average age of 18 months and initial live weight of 274.9 kg were utilized. The animals were maintained on oat + ryegrass pasture and distributed in the following treatments: no supplementation (NS): heifers kept exclusively on pasture; MEG: supplementation with protected fat Megalac®; BRM: supplementation with brown rice meal; BRM+MEG: supplementation with BRM + protected fat. The average final weight of the heifers was of 403.4 kg and corresponded to 89.5% of the adult weight. The body condition of heifers increased linearly with daily increase of 0.012 points, correlating positively with the final weight. There was interaction between treatment and period for average daily weight gain. The highest daily weight gain, 1.395 kg, occurred in the first period when the animals were supplemented with BRM+MEG. In the last period, the NS animals presented the lowest daily weight gain, 0.888 kg. Supplementation with brown rice meal and/or protected fat does not interfere in the intake of pasture by heifers or increase the total intake of dry matter, not changing, therefore, the average daily weight gain at the end of the period of grazing. The daily weight gain does not change during supplementation. The use of temperate pasture with and without supplementation promotes the proper development of the structure and reproductive tract of heifers, benefiting the animal performance indexes in the first mating at 25-27 months of age.

Production parameters of intercropped pastures of oat and rye grass managed with beef heifers supplemented with brown rice meal and/or protected fat were evaluated. Twenty-eight Charolais × Nellore crossbred heifers at initial average age of 18 months and initial average live weight of 274.9 kg were utilized in the experiment. Animals were kept on oat + rye grass pastures and distributed in the following treatments: no-supplementation (NS): heifers kept only in pastures; Megalac (MEG): supplementation with protected fat; brown rice meal (BRM): supplementation with BRM; BRM + MEG: supplementation with BRM plus protected fat. The greater participation of oat leaf was from July 5th to August 10th, 2009 and of rye grass, from August 30th to September 26th, 2009. The crude protein content increased until the 55th day (225.1 g/kg). Pasture total digestible nutrients presented a cubic behavior, with an average of 722.0 g/kg. The highest supply of leaf blades, 5.17 kg of dry matter/100 kg of live weight, was found in the second period. Pasture intake increased throughout the periods. Forage mass and support capacity of the animal did not differ between treatments, presenting means of 1245.02 kg of dry matter/ha and 882 kg of live weight/ha, respectively. Stoking rate, forage loss and pasture intake were not affected by the treatments. Supplementation of beef heifers with rice meal and/or protected fat did not change production parameters of oat + rye grass pastures or pasture intake. Increase in daily accumulation rate of dry matter and supporting capacity of the animals increases forage losses.

The objective of this study was to evaluate behavior patterns of heifers grazing on black oat (Avena strigosa Schreb.) and ryegrass (Lolium multiflorum Lam.), fed supplementation with brown rice meal and/or protected fat. A total of 28 Charolais × Nellore crossbred heifers at average initial age of 18 months and with initial live weight of 274.9±4.97 kg were used in the experiment. Animals were kept in oat + ryegrass pastures and distributed in the following treatments: no supplementation; Megalac (MEG): protected fat supplementation; supplementation with brown rice meal (BRM); and supplementation with BRM + MEG. The neutral detergent fiber (NDF) intake of pasture either in kg or in percentage of live weight was not changed by supply of supplement, but increased linearly (0.045 kg per day) over grazing periods. Supplementation with BRM and BRM + MEG reduced grazing time, 49.63%, in relation to non-supplemented animals and animals supplemented with MEG, 63.13%. Feeding seasons per minute increased over the experimental period with reduction in time spent in each feeding station. The number of bites per feeding station decreased linearly, with a variation of 34.48% in the late grazing period. Heifers supplemented with BRM and BRM + MEG require less time for grazing and increase their idle time, with no modification in displacement patterns within the paddocks and pasture ingestion. Grazing and idle time does not change in the distinct periods of pasture use, but rumination time increases with days of pasture use and with increase in NDF intake.

Avaliaram-se as características da carcaça de novilhos Aberdeen Angus super jovens de biótipos pequeno e médio, terminados em confinamento e abatidos com semelhante espessura de gordura subcutânea. A idade e o peso vivo médio de ingresso no confinamento foram de 298 dias e 202 kg. Os animais foram confinados durante 158 dias, abatidos com espessura de gordura subcutânea média de 6,4 mm. A alimentação foi composta por silagem de sorgo e concentrado, na razão volumoso:concentrado de 60:40 na matéria seca, nos primeiros 63 dias e após, 50:50 até o abate. O biótipo foi calculado utilizando a fórmula B=-11,548 + (0,4878xh) - (0,0289xID) + (0,0000146xID²) + (0,0000759xhxID), em que h representou a altura e o ID idade em dias. Novilhos com biótipo médio apresentaram superioridade nos aspectos importantes de comercialização, como o peso de carcaça quente (p < 0,0001) e fria (p < 0,0001). As medidas de musculosidade da carcaça como a área de longissimus dorsi em relação ao peso de carcaça fria (p = 0,0477) e de corpo vazio (0,0419) foram menores nos novilhos de biótipo médio. A conformação da carcaça, área de longissimus dorsi em cm² e espessura de coxão foram semelhantes entre os biótipos. Os cortes comerciais, dianteiro (p < 0,0001), costilhar (p = 0,009) e traseiro especial (p = 0,0003) em kg foram superiores nos de biótipo médio. Em percentagem, o corte traseiro diminuiu 0,18% com o aumento no biótipo (p = 0,0404). Em peso, os tecidos constituintes da carcaça aumentaram com o biótipo do novilho, já quanto à percentagem o tecido muscular apresentou queda de 0,57% (p = 0,0410).

Carcass characteristics of small and medium-frame Aberdeen Angus young steers, finished in feedlot and slaughtered with similar subcutaneous fat thickness are evaluated. The average age and live weight at the start of feedlot were respectively 298 days and 202 kg. The steers were confined during 158 days, and slaughtered with average subcutaneous fat thickness of 6.4 mm. The feed consisted of sorghum silage and concentrate at 60:40 ratio of dry matter during the first 63 days and 50:50 afterward. The frame was calculated by formula F =-11.548 + (0.4878xh) - (0.0289xID) + (0.0000146xID²)+(0.0000759xIDxh), where h is the height and ID the age, in days. Steers with medium frame showed superiority in important marketing aspects such as warm (p < 0.0001) and cold carcass (p < 0.0001) weights. Muscularity measurements such as longissimus dorsi area in relation to cold carcass (p = 0.0477) and empty body (p = 0.0419) weights were lower for medium-frame steers. Carcass conformation, longissimus dorsi area and cushion thickness were similar in both frame. The commercial cuts, forequarter (p < 0.001), flank (p = 0.009) and saw cut (p = 0.0003) in kg were higher for medium-frame steers. Saw cut decreased 0.18% with an increase in frame (p = 0.0404). Weight of the carcass tissues increased with the steers frame, whereas the percentage of muscle tissue decreased 0.57% (p = 0.0410).

The objective of this research was to study the ingestive behavior of feedlot cows fed additives based on plant extracts or monensin sodium. Twenty-four Charolais and Nellore crossbred cows with age and average initial weight of 7 years and 423 kg, respectively, were used. The experimental diets were plant extracts: basal diet + 5 g/animal/day of a natural additive composed of 750 mg of essential oil of thyme (Thymus vulgaris), 150 mg of garlic (Allium sativum), 250 mg of rosemary extract (Rosmarimus officinalis), 250 mg of canola oil (Brassica napus), 250 mg extract of quillaja (Quillaja saponaria), and 3350 mg of corn starch; sodium monensin: basal diet + 300 mg/monensin/animal/day; and control: basal diet without additive. The basal diet contained sorghum silage and concentrate in a 62:38 ratio. The experimental design was completely randomized with a 3 × 2 (3 diets and 2 breed predominances) factorial arrangement, and means were compared using DMS test at 5% of significance. The type of additive consumed did not alter animal feeding behavior. Cows with Charolais predominance consumed more dry matter (13.78 vs. 12.38 kg/day) and neutral detergent fiber (7.81 vs. 6.89 kg/day), ruminated for longer (8.47 vs. 7.82 h), spent more time chewing (13.05 vs 12.01 h), had a greater number of chews per minute (58.88 vs 53.21) and a greater number of ruminal bolus (541.43 vs. 464.09 boluses/day); however, cows with Nellore predominance had greater idling time (11.82 vs. 10.74 h).

Objetivou-se com este estudo avaliar as características dos componentes externos e da gordura de descarte de novilhos de duas condições sexuais e dois genótipos terminados em confinamento. A idade e o peso médios dos animais ao início do período experimental foram de 12 meses e 267,0 kg, respectivamente. Os novilhos foram confinados até atingirem o peso de abate pré-estabelecido médio de 400 kg. A dieta foi formulada com relação volumoso:concentrado de 50:50, com base na matéria seca, com 10% de proteína bruta. O delineamento experimental utilizado foi o inteiramente casualizado, em arranjo fatorial de 2 × 2, composto de duas condições sexuais e dois grupos genéticos. O peso de corpo vazio (PCV), os rendimentos de carcaça em relação ao peso de corpo vazio e a relação entre o peso de corpo vazio e o peso de abate foram similares entre genótipos e condições sexuais. Para o peso absoluto das orelhas, observou-se interação significativa entre genótipo e condição sexual dos novilhos. Animais castrados apresentaram maiores valores de gordura intestinal em relação ao peso de corpo vazio (1,62 versus 1,18%) e ao peso ao abate (1,41 versus 1,02%) e de cabeça em relação ao peso ao abate (3,78 versus 3,29%). Os animais com predominância de sangue Charolês apresentaram maior peso absoluto de vassoura da cauda (0,16 versus 0,11 kg) e novilhos Nelore maiores pesos relativos de couro e gordura renal. Não há correlação entre o rendimento de carcaça e os componentes não-integrantes da carcaça.

The objective of this study was to evaluate the characteristics of external components and discard fat of young steers with two different sexual conditions and two different genotypes, finished in feedlot. Average age and weight of the animals at the beginning of the experimental period were 12 months and 267.0 kg, respectively. The steers were in feedlot until reaching pre-established slaughter weight of 400 kg. Diet contained roughage:concentrate ratio of 50:50, on dry matter basis, with 10% crude protein. It was used a complete randomized experimental design, in a 2 × 2 factorial arrangement, composed of two sexual conditions and two genetic groups. Empty body weight (EBW), carcass dressing in relation to empty body weight and the relationship between empty body weight and slaughter weight were similar among genotypes and sexual conditions. For absolute weight of ears, it was observed significant interaction between genotypes and sexual conditions of steers. Castrated animals showed greater values of intestinal fat in relation to empty body weight (1.62 versus 1.18%). Animals with Charolais predominance showed greater absolute values to tail broom (0.16 versus 0.11 kg) and Nellore steers predominance presented greater weight related to rawhide and renal fat. There is no correlation among carcass dressing and non-integrant components of carcass.

Este estudo foi realizado para avaliar o comportamento ingestivo de bovinos terminados em confinamento com diferentes níveis de concentrado na dieta. Foram utilizados 16 bovinos não-castrados alimentados com 22, 40, 59 ou 79% de concentrado na dieta, distribuídos em delineamento inteiramente ao acaso, com quatro repetições cada. As dietas fornecidas foram isoproteicas e o volumoso utilizado foi silagem de milho. A coleta de dados ocorreu durante o período de terminação dos animais, totalizando seis dias. O tempo destinado ao consumo de alimento e à ruminação, o número de mastigadas por bolo alimentar e a eficiência na ruminação da fibra em detergente neutro diminuíram linearmente com o aumento dos níveis de concentrado na dieta. O tempo em ócio aumentou linearmente de acordo com o incremento de concentrado na dieta. Quando recebem níveis mais altos de concentrado (79%), os animais apresentam melhor eficiência de alimentação e ruminação.

This study was developed to evaluate the ingestive behavior of beef cattle finished in feedlots with different concentrate levels in the diet. Sixteen bulls fed 22, 40, 59, or 79% of concentrate in the diet were assigned to a complete randomized design, with four replicates each. The supplied diets were isoproteic and the roughage used was corn silage. Data collection was carried out during the finishing period, with a total of six days. The time given to food intake, rumination, the number of bouts per meal and neutral detergent fiber rumination efficiency decreased linearly as the concentrate levels in the diet increased. Idle time increased linearly accordingly to the increment of concentrate in the diet. The animals have greater feed intake and rumination efficiency when fed higher levels of concentrate (79%).

Avaliaram-se as características de carcaça e da carne de novilhos Devon terminados em confinamento, em pastagem temperada (pastagem de azevém -Lolium multiflorum Lam) ou em pastagem tropical (milheto, Pennisetum americanum (L.) Leeke + capim-papuã, Bracharia plantaginea). No início da terminação, os novilhos apresentaram em média 320 kg e 15 meses de idade. Os animais em confinamento foram alimentados com relação volumoso:concentrado de 60:40 e abatidos com pesos semelhantes, de 388,3; 391,5 e 375,8 kg, respectivamente. A terminação em pastagem tropical elevou a idade ao abate de 17 para 19 meses, como resultado do menor ganho de peso médio diário observado em relação ao confinamento e à pastagem temperada. O sistema de alimentação não influenciou os pesos de carcaça quente e fria, nem seus rendimentos, mesmo que as carcaças dos animais terminados em pastagem tropical tenham apresentado maior quebra ao resfriamento em comparação aos da pastagem temperada. A espessura de gordura subcutânea e a conformação nos animais terminados em pastagem temperada foram maiores que naqueles terminados em pastagem tropical, enquanto os animais terminados em confinamento mantiveram-se em posição intermediária. Animais terminados em pastagem tropical apresentaram carcaças com maior porcentagem de ossos e menor porção comestível/osso. Os animais terminados em pastagem temperada apresentaram carcaças com maior espessura de coxão em relação àqueles do confinamento. A carne dos animais terminados em pastagem temperada foi mais escura, apresentou maior força ao cisalhamento e textura mais grosseira, com menor maciez, avaliada pelo painel de degustadores, em comparação à carne daqueles terminados em confinamento ou em pastagem tropicale. Animais terminados em pastagem tropical apresentam carne menos palatável que a de animais terminados em confinamento.

The carcass and meat characteristics were assessed of Devon steers finished in feedlot (CONF), temperate pasture ( ryegrass pasture - Lolium multiflorum Lam -PTEM), or tropical pasture (association of millet pasture - Pennisetum americanum (L.) Leeke and Alexander grass - Brachiaria plantaginea -PTRO). At the beginning of finishing the average weight of the steers was 320 kg and the age was 15 months. The animals in feedlot were fed feeds with 60:40 roughage:concentrate and slaughtered with similar weights of 388.3; 391.5 and 375.8, respectively. Finishing on tropical pasture increased the slaughter age from 17 to 19 months, due to lower average daily weight gain compared to the feedlot and the temperate pasture. The feeding system did not influence the hot and cold carcass weight, nor the hot and cold carcass dressing percentage, even though the carcasses of the animals finished on tropical pasture showed greater chilling loss compared to the temperate pastures. Subcutaneous fat thickness and carcass conformation were higher for the animals finished on temperate pastures than those finished on temperate pasture, while the animals finished in feedlot maintained an intermediary position. The animals finished on tropical pasture presented carcasses with higher bone percentage and lower muscle plus fat/bone ratio. The animals finished on temperate pasture presented carcasses with greater cushion thickness compared to the animals in feedlot. Meat from the animals finished on temperate pasture was darker, had a coarser texture, higher shear force and lower tenderness assessed by a panel of tasters compared to meat from animals finished in feedlot or on tropical pasture. Animals finished on tropical pasture present less palatable meat compared to animals finished in feedlot.

Estudaram-se os efeitos da substituição na dieta da silagem de milho por silagem de girassol (0, 33 e 66% MS) no comportamento ingestivo de novilhos em confinamento. Utilizaram-se nove novilhos castrados com peso vivo e idade média inicial de 288 kg e 20 meses, respectivamente, pertencentes aos grupos genéticos Nelore, 21/32Charolês (C) 11/32Nelore (N) e 21/32N 11/32C. O delineamento experimental utilizado foi o de blocos ao acaso, com três repetições por tratamento. As dietas testadas foram: 100 % de silagem de milho e 0 % de silagem de girassol; 70,94% de silagem de milho e 29,06 % de silagem de girassol; 38,27 % de silagem de milho e 61,73 % de silagem de girassol, todas com relação volumoso:concentrado 60:40. O tempo destinado ao ócio deitado foi maior para os novilhos que consumiram apenas silagem de milho como volumoso em relação aos que consumiram silagem de girassol. O tempo despendido em ócio em pé foi semelhante entre as dietas com 33 (1,84 hora) e 66 % de silagem de girassol (1,96 hora) e menor para aquela sem silagem de girassol (1,62 hora). O tempo em ruminação dos animais aumentou com a inclusão da silagem de girassol na dieta e correspondeu a 8,61; 8,76 e 9,45 horas, respectivamente, para 0; 33 e 66 % de silagem de girassol. Animais alimentados somente com silagem de milho apresentam maior eficiência de ruminação da matéria seca e da fibra em detergente neutro. O tempo despendido por refeição diminui com o aumento da participação da silagem de girassol.

The objective of this experiment was to evaluate the effect of replacing corn silage with sunflower silage (0, 33 e 66% DM) on the ingestive behavior of fedlot steers. Nine castrated steers were used, with average 288 kg initial live weight and 20 month old from the Nellore (N), 21/32Charolais (C) 11/32N and 21/32N 11/32C genetic groups. A randomized complete block experimental design was used, with three replications per treatment. The tested diets were: 100% corn silage and 0% sunflower silage; 70.94% corn silage and 29.06% sunflower silage and 38.27% corn silage and 61.73% sunflower silage, all with a 60:40 roughage:concentrate ratio. Time spent lying idle was greater for steers that consumed only corn silage as roughage compared to those that consumed sunflower silage. Time spent standing idle was similar between 33 (1.84 h) and 66% sunflower silage (1.96 h) and lower for 0% sunflower silage (1.62 h). The animals rumination time increased with the inclusion of sunflower on diet, with values of 8.61; 8.76 and 9.45 h, respectively for 0; 33 and 66% sunflower silage. Animals fed only with corn silage show better dry matter and neutral detergent fiber rumination efficiencies. The time spent feeding decrease with higher participation of sunflower silage.

Este estudo foi conduzido para avaliar o desempenho animal e a viabilidade econômica da utilização de diferentes níveis de concentrado na dieta no confinamento de tourinhos para abate entre 14-16 meses de idade. Foram utilizados 16 bovinos não-castrados alimentados com 22, 40, 59 ou 79% de concentrado na dieta, distribuídos em delineamento inteiramente ao acaso, com quatro repetições por tratamento. A idade e o peso médio inicial dos animais foram de 9,32 meses e 192 kg, respectivamente. A idade de abate, o peso final, o consumo de fibra em detergente neutro, a conversão alimentar e a lucratividade mensal diminuíram com o aumento do nível de concentrado. O consumo de matéria seca em porcentagem do peso vivo e do tamanho metabólicoapresentaram comportamento quadrático, aumentando até os níveis de 67 e 75% de concentrado na dieta, respectivamente. O consumo de energia digestível e o ganho de peso vivo médio diário apresentaram aumentos lineares com a elevação do nível de concentrado. O aumento do nível de concentrado da dieta de 22 para 79% aumenta o desempenho animal, mas reduz a lucratividade da terminação de tourinhos dos 14 aos 16 meses de idade.

This study was conducted to evaluate the performance and economic viability of young bulls slaughtered at 14-16 months old, fed on different concentrate levels in the diet. Sixteen young bulls were randomly distributed and fed with 22, 40, 59 or 79% concentrate in the diet, resulting in four replications per treatment. The initial age and weight were 9.32 months and 192.44 kg, respectively. Final age, final weight, neutral fiber detergent intake, feed conversion and monthly profit decreased with increasing concentrate levels. The dry matter intake as percentage of live weight and metabolic size showed quadratic variation, increasing to 67 and 75% concentrate in the diet, respectively. The digestible energy intake and average daily weight gain increased with increases in concentrate levels. The increase in the level of dietary concentrate from 22 to 79% increased the animal performance, but decreased the profitability of young finished feedlot bulls at 14-16 months old.

Com o objetivo de estudar as características qualitativas da carcaça e da carne de bovinos machos não-castrados abatidos aos 13-14 meses de idade, foram utilizados 16 animais, oito Aberdeen Angus (AA) e oito Hereford (HE), alimentados na fase de terminação com dietas formuladas com dois níveis de energia digestível (ED), o menor 3,07 Mcal/kg de ED (12% de concentrado) e o maior 3,18 Mcal/kg de ED (32% de concentrado). Os animais foram confinados a partir dos 9 meses de idade com peso médio de 220,31 kg e foram abatidos quando, por estimativa, o peso da carcaça atingiu, no mínimo, 190 kg. O delineamento experimental foi o inteiramente casualizado, com quatro tratamentos, em esquema fatorial 2 x 2 (duas raças vs dois níveis de energia). A carne dos animais HE perdeu menos líquido durante os processos de descongelamento e cocção. Além disso, apresentou maior maciez pelo painel de avaliadores e pelo aparelho Shear Force. As carcaças dos animais que receberam o maior nível de energia na dieta apresentaram maior proporção de músculo e, durante o processo de descongelamento, perdeu menos líquido (2,54 vs 7,22%). Quando avaliada pelo aparelho Shear Force, a carne dos animais alimentados com maior nível de energia na dieta mostrou-se mais macia. Verificou-se interação significativa raça <FONT FACE=Symbol>´</FONT> nível de energia para o sabor e a coloração da carne, de modo que a carne dos animais AA, alimentados com menor nível de energia, mostrou-se mais saborosa e com melhor coloração.

The objective of this trial was to study the physical composition of carcass and the qualitative characteristics of the meat of 16 finishing young bulls, eight Aberdeen Angus (AA) and eight Hereford (HE), fed diets with two energy levels (lower: 3.07 Mcal/kg of digestible energy - 12% of concentrate; or higher: 3.18 Mcal/kg of digestible energy - 32% of concentrate). Animals were feedlot fed since 9 months of age and an average body weight of 220.31 kg and were slaughtered when the estimate carcass weight reached at least 190 kg. A completely randomized design with a 2 x 2 factorial arrangement of treatments (two breeds vs. two energy levels) was used. Within breed, meat from HE showed the lowest loss of liquid during thawing and cooking. Meat from HE animals also showed the greatest tenderness when evaluated either by a panel or by the Shear force technique. Animals fed the higher energy diet had greater proportion of muscle, lower loss of liquid at thawing (2.54 vs. 7.22%), and a more tender meat (Shear force) than those fed the lower energy diet. A significant interaction was observed between breed and energy level for both meat flavor and color; AA bulls fed the higher energy diet had meat with greater flavor and better color.

Foram avaliadas as características qualitativas / quantitativas da carcaça de 22 novilhos das raças Charolês ou Nelore, que receberam três níveis de concentrado na dieta: 35; 50 e 65%, durante a fase de terminação em confinamento. Como volumoso, foram utilizadas as silagens de sorgo e de milho. Foi observada interação significativa (P<0,05) entre tratamento e grupo genético para espessura de gordura subcutânea (EG), EG por 100kg de carcaça (EG100) e comprimento de braço. Não houve efeito do nível de concentrado (NC) sobre a EG (3,33mm) e EG100 (1,7) para os novilhos da raça Charolês, enquanto que para os animais da raça Nelore a equação de regressão se mostrou quadrática para estas duas características (EG = 23,62 - 0,759NC + 0,007NC²; EG100 = 14,51 - 0,473NC + 0,004 NC²). Para comprimento de braço (CBR), não houve variação na raça Nelore (38,97cm), enquanto que, na raça Charolês, houve acréscimo linear com o incremento do nível de concentrado na dieta (CBR = 31,98 + 0,098NC). Não foi observado efeito (P>0,05) do nível de concentrado para as demais características de carcaça estudadas. Os novilhos Charolês apresentaram maior peso de abate (372,2 contra 325,6kg), carcaça quente (201,1 contra 180,0kg) e fria (196,1 contra 175,5kg), de traseiro (52,0 contra 43,6kg) e de costilhar (12,4 contra 11,0kg), comprimento de carcaça (118,4 contra 111,8cm), espessura de coxão (25,4 contra 23,3cm), perímetro de braço (39,1 contra 34,6cm), conformação (11,3 contra 9,5 pontos), área do músculo Longissimus dorsi (66,4 contra 53,8cm²) e percentagem de traseiro (52.0 contra 49,4%). Os novilhos Nelore, por sua vez, apresentaram maior comprimento de perna (68,5 contra 58,1cm) e percentagem de dianteiro (38,1 contra 35,5%).

The carcass quantitative characteristics of feedlot finished Charolais or Nellore steers, receiving three levels of concentrated in the diet: 35; 50 and 65%, were evaluated. Sorghum and corn silages were used as roughage. A significant interaction (P<.05) between treatment and genetic group for subcutaneous fat thickness (EG), EG per 100kg of carcass (EG100) and arm length was observed, where no effect of the concentrated level (NC) was observed on EG (3.33mm) and EG100 (1.7) for Charolais steers, while for Nellore steers the regression equation was quadratic for these two characteristics (EG = 23.62 - 0.759NC + 0.007NC²; EG100 = 14.51-0.473NC + 0.004 NC²). For arm length, Nellore steers had any variation (38.97cm), while on Charolais steers, had linear addition with the increment of the concentrated level in the diet (CBR = 31.98 + 0.098NC). Any effect (P>.05) of the concentrated level for the others characteristics studied was observed. The Charolais steers had presented higher slaughter weight (372.2 versus 325.6kg), hot carcass (201.1 versus 180.0kg) and cold carcass (196.6 versus 175.5kg), saw cut weight (52.0 versus 43.6kg) and side cut weight (42.4 versus 11.0kg), carcass length (118.4 versus 111.8cm), cushion thickness (25.4 versus 23.3cm), arm perimeter (39.1 versus 34.6cm), conformation (11.3 versus 9.5 points), Longissimus muscle area (66.4 versus 53.8cm²) and saw cut percentage (52.0 versus 49.4%). The Nellore steers presented higher leg length (68.5 versus 58.1cm) and fore quarter percentage (38.1 versus 35.5%).