Exigências de proteína de bovinos anelorados em pastejo

Paulino²,

et al. 2012

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-The objective of this study was to determine requirements of calcium (Ca), phosphorus (P), magnesium (Mg), potassium (K) and sodium (Na) for grazing zebu bovines. The experiment area was composed of Brachiaria decumbens paddocks. Twenty-seven non-castrated animals, with initial live weight of 311.0 kg and at an average age of 14 months were used. Three animals were slaughtered, after adaptation period, so they were used as control for estimates of empty body weight and initial body composition of animals in the experiment. Out of the 24 remaining animals, four were sent to the maintenance group with restrict grazing time to limit energy intake close to the maintenance level. The other 20 animals were distributed in four treatments: mineral mixture, self-control intake and three-times-a-week-offer frequency (offered on Mondays, Wednesdays and Fridays) and daily. Concentrations of all studied macro elements in empty body and empty body gain decreased as live weight increased. The ratios obtained for g Ca/100 g of retained protein and g P/100 g of retained protein were 9.18 and 4.72, respectively. Total dietary requirement of calcium was lower than the one recommended by NRC (2000), but P requirement was very close to that.

Section: Resultsmentioning

confidence: 99%

Macro mineral requirements by grazing zebu bovines

Paulino²,

et al. 2012

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Exigências proteicas de bovinos de corte suplementados a pasto

Sales¹,

Paulino²,

Filho³

et al. 2010

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RESUMO -Objetivou-se determinar as exigências proteicas de bovinos anelorados, em pastagem com Brachiaria decumbens suplementada com concentrado. Foram utilizados 28 novilhos zebuínos não-castrados com média de 7 meses de idade e 180 kg. Foram abatidos oitos animais-referência para determinação da composição corporal inicial. Os 20 animais restantes foram divididos em cinco lotes de quatro animais, em delineamento inteiramente ao acaso, de modo que cada lote recebeu um dos cinco planos nutricionais: mantença; mistura mineral; e suplementação nos níveis de 0,75; 1,50 e 2,25 kg/animal/dia. A meia-carcaça direita de todos os animais foi dissecada em músculo, gordura e ossos e todos os constituintes do corpo foram pesados para determinação do peso de corpo vazio e da composição corporal. De posse desses dados, procedeu-se ao cálculo das exigências líquidas para ganho de peso em diversas faixas de peso corporal dos animais.Os conteúdos de proteína retidos no corpo dos animais foram regredidos em função do ganho de peso de corpo vazio e da energia retida. As exigências de proteína metabolizável total de um animal de 350 kg e ganho diário de 1,0 kg, foram de 593,59 g/dia. Esse mesmo animal, consumindo 7,40 kg de MS/dia, necessita de dietas com 12,97% de PB na MS total. A exigência líquida de proteína para ganho de peso de animais anelorados não-castrados em pastejo, com até 350 kg de peso corporal, reduzem conforme o peso corporal ou a energia retida aumentam e pode ser estimada a partir da equação: PR (g/dia) = -26,2946 + 247,4853 × GPCVZ -24,8436 × ER. Palavras-chave: exigências nutricionais, proteína, suplementação, zebuínosProtein requirements of pasture supplemented beef cattle ABSTRACT -The objective of this trial was to determine the protein requirements of Zebu bovines on Brachiaria decumbens Stapf. pasture supplemented with concentrate. It was used 28 non-castrated Zebu steers at an average age of 7 months and 180 kg average weight. Eight baseline animals were slaughtered to determine the initial body composition.The 20 remaining animals were divided in five plots of four animals, in a completely randomized design so each group received one out of the five nutritional plans: maintenance; mineral mix; and supplementation at the levels of 0.75; 1.50 and 2.25 kg/animal/day. In all animals, the right half carcass was dissected in muscle, fat and bones and all the body components were weighed to determine the empty body weight and empty body composition. These data allowed the calculations of net requirements forweight gain in several ranges of the body weight of the animals. Contents of protein withheld in the bodies of the animals were regressed in function of empty body gain and withheld energy. The requirements of total metabolizable protein for an animal with 350 kg and average daily weight gain of 1.0 kg, were 593.59 g/day. That same animal, consuming 7.40 kg of DM/day requires diets with 12.97% of CP in total DM. The net requirement of protein for weight gain of non-castrated grazing Zebu bulls with up to 35...

Macromineral requirements by beef cattle under pasture supplementation

Sales

Paulino²,

Filho³

et al. 2011

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-The objective of this work was to determine macromineral requirements by Zebu steers grazing Brachiaria decumbens supplemented with concentrate. It was used 24 non-castrated steers, at an average age of 7 months and at initial average weight 180 kg. Eight control animals were slaughtered for determining initial body composition. The 16 remaining animals were divided in four four-animal plots, in a complete random design. Each plot received mineral mixture or supplements at the levels 0.75; 1.50 or 2.25 kg/animal/day. The right half-carcass of eight animals, two per group, was dissected in muscle, fat and bones and all body constituents were weighted for determination of empty body weight and body composition. Net requirements of calcium and phosphorus for an animal at 400 kg body weight were 11.13 g and 5.40 g, respectively. To estimate dietary requirements of maintenance and after, sum them to dietary requirements for gain in order to obtain total dietary requirements, it was adopted endogenous losses and bioavailability present in literature for each mineral macroelement. Total dietary requirement for calcium, phosphorus, magnesium, sodium and potassium for a 400-kg BW animal with 1.0-kg daily weight gain were 34.59; por grupo, foi dissecada em músculo, gordura e ossos e todos os constituintes do corpo foram pesados para determinação do peso de corpo vazio e da composição corporal. As exigências líquidas de cálcio e fósforo para um animal de 400 kg de peso corporal foram, respectivamente, 11,13 g e 5,40 g. Para estimar as exigências dietéticas de mantença e, posteriormente, somá-las às exigências dietéticas para ganho, no intuito de se obter as exigências dietéticas totais, foram adotadas as perdas endógenas e a biodisponibilidade presentes na literatura para cada macroelemento mineral. As exigências dietéticas totais de cálcio, fósforo, magnesium, sódio e potássio para um animal de 400 kg de PC com ganho diário de 1,0 kg foram, respectivamente, 34,59; 17,36; 7,82; 5,19 e 41,11 g/dia. As exigências em macrominerais de bovinos de corte sob suplementação a pasto são semelhantes às recomendadas pelo BR-Corte para bovinos de corte em confinamento.Palavras-chave: cálcio, exigências nutricionais, fósforo, suplementação, zebuínos Revista Brasileira de Zootecnia