Consumo e digestibilidade em bovinos em pastejo durante o período das águas sob suplementação com fontes de compostos nitrogenados e de carboidratos
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Data
2011-08-01
Autores
Costa, Viviane Aparecida Carli
Detmann, Edenio
Paulino, Mário Fonseca
Valadares Filho, Sebastião de Campos
Carvalho, Isabela Pena Carvalho de [UNESP]
Monteiro, Luana Pereira
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Zootecnia
Resumo
Objetivou-se avaliar os efeitos de diferentes formas químicas de compostos nitrogenados (proteicos e não-proteicos) e de carboidratos (amiláceos e fibra solúvel) sobre o consumo, a digestibilidade e a síntese ruminal de proteína microbiana em bovinos sob suplementação durante o período das águas. Foram utilizados cinco novilhos mestiços Holandês × Zebu, com peso vivo (PV) médio inicial de 211 ± 35 kg, fistulados no rúmen e abomaso. Os tratamentos foram: controle (somente pasto); e suplementos formulados à base de milho + farelo de soja; milho + ureia; polpa cítrica + farelo de soja; e polpa cítrica + ureia. Os suplementos foram balanceados para apresentar 30% de proteína bruta (PB), com base na matéria seca (MS), e fornecidos na quantidade de 3 g/kg PV. O experimento foi conduzido segundo delineamento em quadrado latino 5 × 5, em esquema fatorial 2 × 2 + 1, composto de duas fontes de compostos nitrogenados, duas fontes de carboidratos e tratamento controle. O consumo de pasto reduziu com o fornecimento de suplementos, com coeficiente médio de substituição de 2,11 g de MS de pasto/g de MS de suplemento. A suplementação não alterou os coeficientes de digestibilidade total e ruminação da MS nem o teor dietético de nutrientes digestíveis totais (NDT). Os animais sob suplementação apresentaram maiores coeficientes de digestibilidade total e ruminal da proteína bruta. A eficiência de síntese de proteína microbiana (EFSM), média de 123,1 g PB microbiana/kg de NDT, não foi alterada pela suplementação. Contudo, os animais sob suplementação com milho apresentaram maior EFSM em comparação aos animais sob suplementação com polpa cítrica (137,6 e 106,1 g PB microbiana/kg de NDT, respectivamente). A suplementação proteico-energética para bovinos mantidos em pastos tropicais durante o período das águas não causa benefícios nutricionais, o que reflete o alto coeficiente de substituição da forragem pelo suplemento.
The objective of this work was to evaluate the effects of different chemical forms of nitrogenous compounds (protein and non-protein) and carbohydrates (starch and soluble fiber) on intake, digestibility, and ruminal synthesis of microbial protein in cattle supplemented during rainy season. It was used five crossbred Holstein × Zebu steers, with average initial body weight of 211 ± 35 kg and fistulated in the rumen and abomasum. The treatments were: control (only pasture), and supplements based on corn + soybean meal; corn + urea, citrus pulp + soybean meal, and citrus pulp + urea. The supplements were balanced to present 30% of crude protein (CP), on dry matter (DM) basis, and provided at 3 g/kg BW. The experiment was carried out according to a 5 × 5 Latin square design in a 2 × 2 + 1 factorial arrangement, composed of two sources of nitrogenous compounds, two sources of carbohydrates and a control treatment. Pasture intake was reduced when supplements were fed to animals, with average substitution coefficient of 2.11 g of DM of pasture/g of DM of supplement. Supplementation did not alter the total and ruminal digestibility coefficients of DM and the dietary content of total digestible nutrients (TDN) neither. Supplemented animals presented higher ruminal and total digestibility coefficients of CP than non-supplemented animals. The efficiency of microbial protein synthesis (EMPS), average of 123.1g of microbial CP/kg, was not changed by supplementation. However, animals supplemented with corn presented higher EMPS in comparison to animals supplemented with citrus pulp (137.6 and 106.1 g microbial CP/kg of TDN, respectively). Protein-energy supplementation for cattle grazing in tropical pastures during rainy season does not cause nutritional benefits, which reflects the high coefficient of substitution of forage by the supplement.
The objective of this work was to evaluate the effects of different chemical forms of nitrogenous compounds (protein and non-protein) and carbohydrates (starch and soluble fiber) on intake, digestibility, and ruminal synthesis of microbial protein in cattle supplemented during rainy season. It was used five crossbred Holstein × Zebu steers, with average initial body weight of 211 ± 35 kg and fistulated in the rumen and abomasum. The treatments were: control (only pasture), and supplements based on corn + soybean meal; corn + urea, citrus pulp + soybean meal, and citrus pulp + urea. The supplements were balanced to present 30% of crude protein (CP), on dry matter (DM) basis, and provided at 3 g/kg BW. The experiment was carried out according to a 5 × 5 Latin square design in a 2 × 2 + 1 factorial arrangement, composed of two sources of nitrogenous compounds, two sources of carbohydrates and a control treatment. Pasture intake was reduced when supplements were fed to animals, with average substitution coefficient of 2.11 g of DM of pasture/g of DM of supplement. Supplementation did not alter the total and ruminal digestibility coefficients of DM and the dietary content of total digestible nutrients (TDN) neither. Supplemented animals presented higher ruminal and total digestibility coefficients of CP than non-supplemented animals. The efficiency of microbial protein synthesis (EMPS), average of 123.1g of microbial CP/kg, was not changed by supplementation. However, animals supplemented with corn presented higher EMPS in comparison to animals supplemented with citrus pulp (137.6 and 106.1 g microbial CP/kg of TDN, respectively). Protein-energy supplementation for cattle grazing in tropical pastures during rainy season does not cause nutritional benefits, which reflects the high coefficient of substitution of forage by the supplement.
Descrição
Palavras-chave
amido, fibra solúvel, suplementação proteico-energética, ureia, energy-protein supplementation, soluble fiber, starch, urea
Como citar
Revista Brasileira de Zootecnia. Sociedade Brasileira de Zootecnia, v. 40, n. 8, p. 1788-1798, 2011.