Conteúdo Corporal e Exigências Líquidas de Proteína e Energia de Novilhos Suplementados no Período das Águas

Abstract

RESUMO -Avaliaram-se os efeitos da suplementação concentrada de novilhos, durante o período das águas, sobre os conteúdos corporais de proteína e energia e as respectivas exigências líquidas para ganho de peso. Foram utilizados 49 novilhos mestiços, mantidos em pastagem de Brachiaria decumbens. O experimento foi conduzido em três períodos experimentais, segundo delineamento inteiramente casualizado. Foram fornecidos diariamente sal mineral (SAL), suplementos à base de milho e farelo de soja, com 20% PB, em nível de 1,0 e 2,0 kg/dia (MFS1 e MFS2), respectivamente, e suplementos à base de farelo de trigo e farelo de soja, com 20% PB, em nível de 1,0 e 2,0 kg/dia (FTFS1 e FTFS2), respectivamente. Não foram encontradas diferenças entre os tratamentos sobre os conteúdos corporais de proteína e energia para os tratamentos SAL, MFS1, MFS2, FTFS1 e FTFS2. Os animais submetidos aos diferentes tratamentos não exibiram diferenças na composição do ganho de peso para proteína, gordura e energia. As exigências líquidas de proteína e energia para um animal de 350 kg de peso vivo foram, respectivamente, de 220 g e 5,75 Mcal por kg ganho de peso vivo.Palavras-chave: conteúdo corporal, exigências nutricionais, suplementos, pastagem Body Composition and Net Requeriments of Energy and Protein of Supplemented Steers during the Rainny SeasonABSTRACT -The effects of concentrate supplementation of stocked an during the rainny season on the body composition of energy and protein and net requirements of protein and energy for weight gain were evaluated. Forty-nine crossbred steers, were Brachiaria decumbens pastures, were used. The experiment was driven in three experimental periods, according to a completely randomized design. The following supplements were daily fed at 10 a.m.: mineral salt (SALT), supplements based on corn and soybean meal, with 20% CP, at the level of 1.0 and 2.0 kg (CSBM1 and CSBM2) and supplements based on wheat bran and soybean meal, with 20% CP, at the level of 1.0 and 2.0 kg (WMSBM1 and WMSBM2). The animals submitted to the different treatments showed no differences on composition of weight gain in the protein, fat and energy. The net requirements of protein and energy for an animal with 350 of body weight were, respectively, 220 g and 5. . Zootec., v.31, n.1, p.530-537, 2002 (suplemento) R. Bras IntroduçãoDentro de uma perspectiva ecológica, a obtenção de um produto animal a partir de forragens envolve a produção da planta, sua conversão para produto, a eficiência de conversão e seu valor econômico dentro dos limites das barreiras ecológicas. O animal em pastejo se insere em um ciclo que se altera dinamicamente, influenciado pelo ambiente e por mudanças nos requerimentos e no suprimento de forragem (Noller et al., 1996).A qualidade da forragem pode ser determinada em termos do desempenho animal obtido quando esta forragem é fornecida ao animal (Penati et al., 1999). O desempenho animal é função do consumo de nutrientes digestíveis e metabolizáveis. Da variação existente no consumo da matéria seca (MS) digestí...

Body composition and energy and protein requirements of grazing Nelore steers

“…This value is lower than that recommended by the NRC (2000), of 0.8910 and 0.8975 and 0.8956 reported, respectively, by Silva et al (2002a) and Paulino et al (2004ab), obtained from Nellore animals in feedlot confinement. Empty body weight to BW ratio of 0.8360, observed in this work, was close to 0.8575, reported by Zervoudakis et al (2002), working with Holstein × Zebu crossbred steers, and 0.8506, observed by Fregadolli (2005) working with Nellore animals, both experiments carried out on pasture. This difference between animals raised in feedlot and pasture may be justified by the influence of the level of supplement offer and particle size ingested in EBW, whereas animals with higher forage intake showed greater content retention in TGI, therefore the EBW:BW ratio was lower (Owens et al, 1995).…”

“…The results are consistent with those observed for animals reared on pasture (Zervoudakis et al, 2002;Fregadolli, 2005) and for animals reared in feedlot confinement (Silva, 2002a;Paulino et al, 2004a, Freitas et al, 2006. According to Berg & Butterfield (1976) as the weight increases, the concentration of fat in the body increases, with a consequent increase in energy requirements, because there is an increase in energy value of the gain with the increase in animal BW.…”

Body composition and net protein and energy requirements for weight gain of crossbred dairy cattle in grazing

“…According to Berg & Butterfield (1976), the bone tissue presents higher growth at very early age, followed by muscle tissue in intermediate ages and fat tissue in elderly. As can be evidenced, the fat content in the gain increased as BW or EBW increased for animals from each diet and for the entire dataset, which strengthens the reports of Zervoudakis et al (2002) and Fregadolli (2005) in researches with dairy crossbred animals in pasture.…”

“…The regression coefficients (b) of the equations (Table 1) showed an increase in the protein content to rates relatively equal to the increase in the empty body weight, similar behavior to that observed by Zervoudakis et al (2002). According to Jorge et al (2003), bone tissues presents low growth coefficient (b<1) being considered early; muscles have intermediate growth (b = 1) while fat is high (b>1).…”

“…The empty body weight of an animal of 200 kg of live weight, estimated from the equation above (147.07 kg) was 17.8 and 10.5% higher than that obtained by Zervoudakis et al (2002) and Fregadolli (2005), respectively, working on dairy castrated crossbred animals raised on pasture with supplementation, and 17.4% lower than the value of 178.2 kg recommended by the NRC (1996): EBW = BW * 0891. The lowest values found in this study, compared to the NRC (2000), it may be in part related to the higher content in the gastrointestinal tract of animals maintained in pasture.…”