Avaliação de características produtivas e nutricionais de sorgo (Sorghum bicolor L. Moench) para silagem, nas condições edafoclimáticas do Estado do Rio de Janeiro

Abstract

The purpose of this experiment was to compare twenty five highly productive and nutritive genotypes of sorghum silage, cultivated in soil and climate conditions of center-south region of Rio de Janeiro State. Twenty five genotypes of sorghum had been compared, being twenty two advanced hybrids (not released to be sold yet), that integrate of the Ensaio Nacional de Sorgo Forrageiro, CNPMS/EMBRAPA, and three commercial hybrids. The harvest of cropping to be ensilado was carried through between ninety five and one hundred days after they have been planted, being cut at 10 cm from the ground. After have been harvested the material was immediately weighed for measure yield per hectare and later packed in laboratorial silos, made in PVC. The experimental design was of randomized blocks. The silos had been opened after 60 days and material were weighed for determination of partial dry matter. A sample of five gram of each hybrid was milled in Willey micro mill type with mash of one millimeter to determine dry matter (DM), crude protein (CP), neutral detergent fiber (NFD), acid detergent fiber (AFD), cellulose (CEL), lignin (LIG) and “in vitro” dry matter digestibility (IVDMD). The remain material was milled in five millimeters mash bolter for determination of “in situ” dry matter digestibility (ISDMD), on CNPGL’s Laboratory. The digestibility assay was composed for three rumen canullated crossbred Friesian x Zebu cows weighing 505,3 kg, in the beginning of lactation, producing 17.5 kg of milk. Approximately five grams of each sample was putted into a nylon bag. All the animals had received all the samples in all the three incubation times (6, 24 and 96 hours). The experimental designed for digestibility assay was randomized in split-plot