Degradabilidade in situ da matéria seca de feno e silagem de capim Marandu (Urochloa Brizantha cv. Marandu), cultivado em diferentes sistemas

Abstract

The aim of this study was to evaluate the in situ degradability of dry matter of hay and silage of the grass Urochloa brizantha cv. Marandu, cropped with 150 d, in monoculture and simultaneous cultivation with maize. The forage was planted in three different paddocks “A,” “B” and “C” as single grass, Marandu grass intercropped with maize without suppression, and using Nicosulfuron herbicide suppression, respectively. Samples were collected from each paddock for hay and silage making. Silos were opened with 40 days. In situ degradability evaluation of both hay and silage were conducted at the Animal Nutrition Department at the Federal University of Grande Dourados. For the incubation, a rumen-fistulated bovine of 450 kg average weight, castrated, in an individual paddock of Marandu grass with water drinker and mineral supplementation trough was used. Samples of hay and silage were incubated into the bovine rumen in the descending order of 96, 72, 48, 36, 24, 12, 9, 6, 3, and 0 hours. Samples of intercropped grass presented a decrease of 34% of the effective degradability in contrast to the single grass. Despite of the grass age, it presented similar values of NDF and ADF found in the literature. The means of crude protein (CP) were greater than those found by other authors. The suppression with herbicide promoted a CP decrease in both hay and silage. However, the suppression did not cause damages to the potential degradability. The feeds potential degradability was average to high.