Níveis de suplementação para novilhos da raça Nelore terminados a pasto na região centro-oeste durante o período da seca / Supplementation levels of Nelore steers in finishing phase on pasture on central Brazil during the dry season

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The present dissertation was elaborated from two experiments that evaluated the effect of six supplementation levels on performance, fat thickness, carcass yield, intake and digestibility in steers. In the first experiment, the objective was to evaluate the weight, the average daily gain and the carcass characteristics of Nelore steers supplemented with different levels of protein and energy in the finishing phase during the dry period, and to evaluate the available of the components of the pasture. The experiment was implanted in pasture of Brachiaria brizantha, cv. Marandu, in twelve paddocks of nine hectares. Ninety-six Nelore steers with 30 months age and initial weight of 412+16 kg were distributed at random in twelve groups of eight animals. Each group was allocated in a paddock, being weighted in the beginning and every 21 days, during 84 days. Increasing levels of two types of supplements were used, based on corn or soybean meal: 0.25, 0.5, 1.0, 2.0, and 4.0 kg/animal/day, in addition to a two control groups receiving mineral mixture. Each supplement type, except the control, presented decreasing levels of crude protein (87.4 to 25.0% of the dry matter for corn basis supplements; and 110.8 to 31.9% for soybean basis supplements) and proportions of mineral mixture:urea:concentrate feeds of 25:25:50, 15:15:70, 10:10:80, 5:5:90, and 2.5:2.5:95 for the treatments 0.25, 0.5, 1.0, 2.0, and 4.0 kg/animal/day, respectively. The treatments were evaluated by regression in a completely randomized design. The proportion of stem and dead leaf increased in elapsing of the experimental periods characterizing the dry season. There was increasing linear effect on the final live weight, average daily gain and average daily gain by a period as a function of the supplement intake, and average daily gain as a function of the crude protein and total nutrients digestible intake for both types of supplements. For the average daily gain there was no effect of supplement type. There was increasing linear effect on the carcass weight and fat thickness for the two supplement types. For the carcass yield there was increasing linear effect for the supplements based on soybean meal and quadratic effect for the supplements based on corn. In a second experiment, the objective was to evaluate the effect of the supplementation with different levels of protein and energy on the intake and digestibility of Nellore steers in finishing phase on pasture during the dry season. The experiment was implanted on pasture of Panicum maximum cv. Tanzânia, in eight paddocks of one hectare. Eight Nellore steers with 30 months and initial weight of 440 kg were used. The animals were distributed in two 4x4 Latin squares (supplementation levels and periods). Increasing levels of two types of supplements were used, based on corn or soybean meal: 0.0, 1.0, 2.0, and 4.0 kg/animal/day, in which the 0.0 was a control group receiving mineral mixture. Each supplement type, except the control, presented decreasing levels of crude protein (42.6 to 52.0% for corn based supplements; and 57.5 to 31.9% of the dry matter for soybean meal based supplements) and proportions of mineral mixture: urea: concentrate feeds of 10:10:80, 5:5:90 and 2.5:2.5:95 for the treatments 1.0, 2.0, and 4.0 kg/animal/day, respectively. Each experimental period was constituted of 16 days, in a total of 64 days. The intake and the digestibility were through the relationship among the amount of fecal dry matter excreted by using an external indicator (Cr2O3) and an internal indicator (ADFi). The 4x4 Latin square were evaluated by regression analyzes. There was increasing linear effect for dry matter intake in kg/animal/day and % of BW, and intakes of crude protein ethereal extract, neutral detergent fiber and total digestible nutrients, and there was no effect on the intake of pasture, for both supplement types. For the non-fibrous carbohydrates intake there was increasing linear effect for the supplements based on corn and there was no effect for the treatments based on soybean. For the corn based diets there was increasing linear effect for the digestibility of the dry matter and neutral detergent fiber. For the coefficients of digestibility of the crude protein, ethereal extract and non-fibrous carbohydrates there was not effect. For the supplements based on soybean there was increasing linear effect for the digestibility of the dry matter, crude protein, ethereal extract and neutral detergent fiber, and there was not effect for the non-fibrous carbohydrates.

ASSUNTO(S)

soja nelore (bovino) maize soybean supplementation milho nutricao e alimentacao animal bovine suplementação performance desempenho

ACESSO AO ARTIGO

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