Fermentation quality and protein fractions of four Pennisetum grass silages

Abstract

In order to make good use of Pennisetum grasses to relieve the shortage of animal feed, the nutrients, silage fermentation quality, and Cornell Net Carbohydrate and Protein System (CNCPS) protein fractions of Pennisetum spp. were evaluated in this study. Four Pennisetum cultivars of Reyan-4, Mott, Guimu-1, and MT-1 were harvested at the first cut and second cut, and they were wilted and ensiled for the analyses of fermentation quality and protein fractions. The first-cut grasses had higher crude protein (CP), water-soluble carbohydrate (WSC) contents, and lower detergent fiber contents than the second cut ones. Mott had higher CP content. Reyan-4 and MT-1 contained higher WSC contents, and their silages had lower pH and ammonia nitrogen (NH₃-N) content, higher lactic acid content than Mott and Guimu-1 silages. Wilting increased pH and NH₃-N contents and decreased lactic acid contents of both cut silages. The CNCPS analysis showed that fresh MT-1 of either first or second cut had more evenly distributed protein fractions than other three grasses. Wilting and ensiling increased nonprotein nitrogen contents and decreased unavailable protein contents of four grasses. Four cultivars at the first cut contained more CP and less fiber than those at the second cut. Reyan-4 and MT-1 had better fermentation quality of silage than Mott and Guimu-1; the latter might need additives to improve fermentation quality at ensiling.