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摘要
Este trabalho objetivou avaliar a composi o corporal e exig那ncias nutricionais de c芍lcio e f車sforo de cordeiro em sistema de pastejo na regi o semi-芍rida brasileira. Foram utilizados 32 cordeiros Santa In那s, castrados, com peso m谷dio inicial de 15,8 ㊣ 1,4 kg e idade entre tr那s e quatro meses. Destes, oito foram abatidos no in赤cio do experimento representando a composi o corporal inicial (animais-refer那ncia) na metodologia do abate comparativo 角 medida que atingiam 15 kg. Os demais animais foram distribu赤dos aleatoriamente em tr那s lotes com tr那s n赤veis de suplementa o, sendo um para cada tratamento; quando o primeiro animal de cada lote atingia 30 kg, o respectivo lote era abatido. Os animais estavam em pastagens nativas enriquecidas com capim-buffel e suplementados com tr那s diferentes n赤veis de mistura concentrada na dieta, correspondendo 角 suplementa o de 0,0; 1,0 e 1,5% de concentrado por dia. Os valores estimados de composi o corporal variaram de 17,11 a 14,91 g de Ca; 6,08 a 5,33 g de P por kg de peso de corpo vazio (PCV). As exig那ncias l赤quidas de cordeiros de 15 a 30 kg para ganho de peso variaram de 10,8 a 9,4 mg, para Ca, e 3,89 a 3,76 mg, para P, por g de PV ganho. This work aimed to evaluate the body composition and the calcium and phosphorus nutritional requirements of Santa In那s lambs under rangeland conditions in the semi-arid region of Brazil. Thirty-twocastrated lambs between 3 to 4months old were used, with an initial mean body weight of 15.8 ㊣ 1.4 kg. Of these, eight were slaughtered in the beginning of the experiment to provide the initial body composition (※Reference Animals§ of the comparative slaughtermethod). The other animals were divided randomly in groups of three, as the lambs reached 15 kg. The three levels of food supplementation were randomly assigned to the lambs in each group (block). When the first animal in each group reached 30 kg, the whole group was slaughtered. The animals were kept in native rangeland enriched with buffelgrass (Cenchrus ciliaris L. cv. Biloela). Their diets were supplemented daily with three levels of concentrate mixture (0.0, 1.0 and 1.5% of their body weight). The estimated values of bodycomposition, in g kg-1 of empty body weight, ranged from 14.91 to 17.11 g for Ca, and from 5.33 to 6.08 g for P. The net requirements gain of 15-to-30-kg lambs, in g kg-1 gained in live body weight, ranged from 9.4 to 10.8 mg for Ca, and from 3.76 to 3.89 mg for P.
