ABSTRACT The objective of this study was to evaluate the production performance of feedlot cattle fed diets containing chopped sugarcane ratios (580 or 380 g/kg of diet dry matter) as roughage and levels of inclusion of babassu mesocarp bran (BMB; 420 to 620 g/kg of concentrate dry matter). Twenty-four young Nellore bulls with 321±23 kg initial body weight, at 22 months of age, were used in a completely randomized experimental design with treatments in a 2 × 2 factorial arrangement and six replicates. Dry matter intake (21.71 g/kg of body weight), average daily gain (1.46 kg/day), and cold carcass weight (232.59 kg) were not changed by proportion of sugarcane or BMB level. The proportions of sugarcane and BMB levels did not change the apparent digestibility of the diets, except the digestibility of neutral detergent fiber, which was lower in the diet associating the lowest levels of sugarcane and BMB. Increasing proportions of sugarcane reduced subcutaneous fat thickness from 2.89 to 1.91 mm. Carcass commercial primal cuts were not affected by variation factors. Inclusion of babassu mesocarp bran enables the use of larger proportions of sugarcane as a result of the increased digestibility of the fiber fraction of feedlot cattle diets without changing the performance and main carcass traits of these animals.

O objetivo foi avaliar o desempenho e as características de carcaça de tourinhos terminados em confinamento alimentados com dietas contendo cana-de-açúcar (Var. SP 80-1816) e dois níveis de concentrado (40 ou 60 % da MS). Foram utilizados 15 animais da raça Nelore com aproximadamente 330 kg e 18 meses de idade e 15 da raça Canchim com aproximadamente 300 kg e 15 meses de idade. Os animais foram alojados em baias individuais por um período de 126 dias (os primeiros 21 dias foram de adaptação). Foram realizadas pesagens e tomadas imagem ultrassônicas, ao início do experimento e a cada intervalo de 35 dias. O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 2 ×2, composto de 2 grupos genéticos e 2 níveis de concentrado. Não foi observada interação fatores ×variáveis estudadas. Os animais da raça Canchim apresentaram melhor eficiência alimentar (0,17 ×0,14) e maior ganho de área de olho-de-lombo (19,7 ×13,2 cm²). A dieta contendo 60% de concentrado, em comparação àquela com 40%, proporcionou maior ganho de peso diário (1,44 ×0,98 kg/animal), maior peso de abate (499,43 ×460,20 kg), de carcaça quente (265,39 ×244,70 kg) e de traseiro especial (129,74 ×118,68 kg). Os animais da raça Canchim apresentaram maior área de olho-de-lombo (80,89 ×66,85 cm²) e os animais Nelore maior cobertura de gordura (5,5 ×3,2 mm). Dietas com 60% de concentrado são mais indicadas para terminação de bovinos com elevado potencial de ganho de peso que aquelas com 40%.

The objective of this study was to evaluate the performance and carcass traits of young bulls, finished in a feedlot and fed diets with sugarcane (Var. SP 80-1816) and two concentrate levels (40 or 60 % of the DM). Fifteen Nellore bullocks, with approximately 330 kg and 18 months old, and 15 Canchim bullocks (5/8 Charolês ×3/8 Nellore), with approximately 300 kg and 15 months old, were used. The animals were housed in individual pens for a period of 126 days, with the first 21 days of adaptation. The animals were weighed and ultra-sound images were taken at the beginning of the experiment and at every 35 days. A randomized complete design was used in a factorial scheme (2 genetic groups ×2 concentrate levels). There were no significant interactions for any of the evaluated variables. The Canchim animals presented better feed efficiency (0.17 ×0.14) and higher loin eye area gain (19.7 ×13.2 cm²). The 60% concentrate diet improved better daily weight gain (1.44 ×0.98 kg/animal), slaughter weight (499.43 ×460.20 kg), hot carcass weight (265.39 ×244.70 kg) and hindquarter weight (129.74 ×118.68 kg). The Canchim animals presented larger loin eye area (80.89 ×66.85 cm²) and the Nellore animals presented thicker backfat (5.5 ×3.2 mm). Diets with 60% concentrate are better for finishing cattle with high potential for liveweight gain than diets with 40% concentrate.

O objetivo nesta pesquisa foi avaliar o efeito de dois ingredientes protéicos da dieta (farelo de soja e de algodão) e de dois processamentos físicos do concentrado (farelado e extrusado) na terminação de 16 bovinos machos não-castrados da raça Canchim. Avaliaram-se ainda a excreção de nutrientes nos dejetos e o potencial de produção de biogás. Os animais tinham 12 meses de idade e 315 kg PC, em média, e foram confinados em baias individuais durante 147 dias (os primeiros 35 dias foram de adaptação). Como volumoso utilizou-se silagem de milho, em uma relação volumoso:concentrado de 50:50, com base na MS. Os resultados foram analisados em delineamento inteiramente casualizado, em esquema fatorial 2 × 2 (fonte protéica × processamento físico). A fonte protéica influenciou o ganho de peso corporal (1,50 e 1,35 kg/dia para o farelo de soja e de algodão, respectivamente), a conversão alimentar (4,73 e 5,31 kg MS ingerida/kg de ganho de peso, respectivamente) e a eficiência protéica (1,78 e 1,59 kg de ganho de peso/kg PB ingerida, respectivamente). O tratamento físico do concentrado e a fonte protéica não influenciaram a ingestão de MS, a área de olho-de-lombo e a espessura de gordura, estimadas por ultra-som. O balanço de nutrientes foi semelhante entre tratamentos para MS, FDN e FDA, mas a fonte protéica determinou diferenças no balanço de PB. Entre os macro e microminerais quantificados nas fezes, os teores de P e Mg diferiram entre as fontes protéicas e a extrusão aumentou o conteúdo de Ca, com médias de 0,39 e 0,43 g/100 g de MS de dejetos, respectivamente, para os concentrados farelado e extrusado. Os dejetos produziram biogás de maneira efetiva entre o 70º e o 200º dia.

The objective of this research was to evaluate the effect of two protein ingredients of the diet (soybean and cottonseed meals) and two physical process of the concentrate (grounded and extruded) upon the finishing of 16 Canchim young bulls. It was evaluated also the nutrients excretion in feces and biogas production potential. The animals were 12 month-year-old, with initial 315 kg BW, and they were confined in individual pens for 147 days, being the first 35 days of adaptation. The roughage used was corn silage and the forage:concentrate rate was 50:50, on dry matter basis. The results were analyzed in a total randomized design, in a 2 × 2 factorial arrangement (protein source x physical process). There was effect of protein source upon the body weight gain (1.50 and 1.35 kg/day with soybean and cottonseed meal, respectively), feed conversion (4.73 and 5.31 kg DM intake/kg weight gain, respectively) and protein efficiency (1.78 and 1.59 kg weight gain/kg CP intake, respectively). There was no difference among treatments for DM, loin eye area and subcutaneous fat thickness, evaluated by ultra-sound. The nutrient balance was similar among treatments for DM, NDF and ADF, but protein source caused differences in CP balance. Among the macro and microminerals determined in feces, P and Mg contents were different among protein sources, and extrusion increased Ca content, with means of 0.39 and 0.43 g/100 g dejections dry matter, respectively for grounded and extruded concentrate. The dejections produced biogas effectively from 70th to 200th days.