Perdas na ensilagem e desempenho de bovinos de corte suplementados com dietas contendo silagem de capim-marandu em duas idades de rebrotação tratadas com inoculante bacteriano / Silage losses and performance of beef cattle fed diets with Marandu grass silages at two ages of regrowth treated with bacterial inoculant

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

17/02/2011

RESUMO

Three experiments were carried out to evaluate intake and the partial and total nutrient apparent digestibilities, nitrogen compounds balance, microbial efficiency, rumen traits and the performance of beef cattle fed diets based on Brachiaria brizantha cv Marandu at two ages of regrowth with and without microbial inoculant Sil ALL C4 (Alltech Brazil), as well as to determine losses and the chemical composition of these silages. In Experiment 1, it was evaluated fermentation profile, chemical composition, the losses and recovery of dry matter of Marandu grass silages at two ages of regrowth (35 and 70 days), with and without inoculation by using 18-L buckets. A 2 × 2 scheme was used (two regrowth ages × with and without inoculation) in a complete random experimental design with five replications. It was observed an effect of age at regrowth × inoculant on the dry matter (DM) content. For contents of neutral detergent insoluble fiber corrected for ash and protein (NDFap), acid detergent insoluble fiber (ADF), crude protein (CP) and acid detergent insoluble nitrogen (ADIN), effect was observed only on regrowth age. Concentrations of lactic acid, propionic acid and butyric acid were influenced by the interaction age × regrowth inoculant (P <0.05) and the greatest value of lactic acid in silage plants cut at 70 days of regrowth was recorded. It was observed effect of the (P <0.05) age × inoculant regrowth interaction on the gas production. For effluent production, it was observed age effect, with the greatest value in the silage plants cut at 70 days of regrowth. On the other hand, dry matter recovery was influenced by inoculant (P <0.05) and the age at regrowth (P <0.05), with the greatest values found in the inoculated silage and in that of plants harvested at 70 days regrowth. In Experiment 2, it was used 32 crossbred Holstein-Zebu (HxZ) bulls, with average initial body weight (IBW) of 364 20.00 kg. The animals were distributed in a 2×2 factorial design in seven randomized blocks to evaluate intake, nutrient digestibility and production performance. The diets consisted of 50% Marandu grass silage and 50% of concentrate at the dry matter basis. The silages from plants cut at 35 and 70 days, additived or not with inoculant. There was no effect (P>0.05) of diets on nutrient intake, except for neutral detergent insoluble fiber (NDF), which was affected by the age of regrowth. Total nutrient digestibility, average daily gain (ADG), feed conversion (FC) and carcass dressing (CD) were not affected (P>0.05) by the diets. In Experiment 3, it was used four castrated crossbred steers (H×Z), with IBW of 267 12.00 kg, fistulated in the rumen and abomasum, distributed in a 4x4 Latin square to evaluate the intake and total and partial apparent digestibility of nutrients, rumen characteristics and microbial efficiency. The animals were fed the same experimental diets from the previous experiment. There was no effect (P>0.05) of diets on the nutrient intake. It was observed an effect of age on rumen and intestinal non-fibrous carbohydrate apparent digestibility. However, total and partial apparent digestibilities of other nutrients were not affected by the diets. There was no effect (P>0.05) of experimental diets on cutting period, nor the interaction of these factors on N-NH3 concentration, whereas rumen pH was influenced (P <0.05) only by cutting period, with the minimum value estimated from 6.26 to 4.13 hours after feeding. The two silages can be classified as good quality ones based on the pH and N-ammonia characteristics which are within the acceptable range for proper preservation of grass silage. Inoculation of Brachiaria brizantha cv Marandu cut at 35 and 70 days of regrowth with microbial inoculant Sil ALL C4 (Alltech Brazil), does not affect intake, nutrient digestibility, rumen traits and performance of beef cattle fed silage of Brachiaria brizantha cv Marandu cut at 35 and 70 days of of regrowth.

ASSUNTO(S)

consumo pastagem e forragicultura digestibilidade desempenho produtivo intake digestibility productive performance

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