Efeito da ensilagem sobre a cinética de degradação de clones de capim-elefante (Pennisetum sp.).

Abstract

The objective was to evaluate the effect of ensilage 5 clones of elephant grass (Pennisetum sp.) on the degradability in sheep. The forages evaluated were three clones of short stature (Mott, Taiwan A-146 2.27 and Taiwan A-146 2.37) and two tall (Elephant B and IRI 381), that at 70 days were cut, ensiled in PVC silos and open to 120 days. For evaluate the effect of ensiling on the degradation were four sheep, with average weight of 40 kg, fitted with permanent rumen fistula, where bags were incubated (7x4 cm, 40 μm) in duplicate, containing approximately 1.6 g sample of each material per animal. Incubation times used were 0, 3, 6, 12, 24, 48, 72 and 96 hours and removed from the rumen samples were taken in descending order. For each incubation time was determined by the disappearance of DM, used to estimate the potential and effective degradability. The silages had low NH3-N, within the range indicated for the preservation and proper pH. Differences degradability after ensiling, but most clones remained with degradations similar to its fresh form, while Taiwan A-146 2.27 has increased degradation after ensiling. When comparing the effect of silage and incubation times, it was observed that there was an increase over time degradability of DM and NDF within 72 hours. After fermentation, the degradation was higher for Taiwan A-146 2.37. The soluble fraction, in the form of silage decreased some clones, except Taiwan A-146 2.27 and Taiwan A- 146 2.37, which are of short stature. ND fraction of DM in the rumen was significant only among clones, with no end in the form and saved to NDF was not significant. The fraction b and c fraction showed no significant difference for DM and NDF. The DP showed no interaction of forage types and clones. The forms silage decreased the effective degradability in the observed rates of 2, 5 and 8% / h. The NDF (2% / h) showed no differences after the ensiling process allowing you to maintain the degradation. In the passage rates of 5 and 8% / h clones Elephant and IRI 381 B degradation decreased significantly after the fermentation process. All clones showed good fermentation after ensiling and the smaller clones had greater degradation.