Effects of Harvesting Different Sorghum-Sudan Grass Varieties as Hay or Silage on Chemical Composition and Digestible Dry Matter Yield

摘要

The objective of this study was to evaluate the harvesting different sorghum-sudan grass varieties as hay or silage on chemical composition, digestible dry matter and crude protein yields under eastern Anatolia conditions. The sorghum-sudan grass hybrids were harvested by hand, weighed and air-dried to conserve as hay when they were approximately 150 cm tall. After air-drying, approximately 100 g of sub-sample were taken for determinations of dry matter, chemical composition and in vitro DM digestibility of hays. To conserve as silage, the sorghum-sudan grass hybrids were harvested by a one-row forage harvester at dough stages of kernel maturity and were ensiled in mini-silos (1L in volume) in triplicate for each variety. Packing was accomplished by hand-power. After 60 d of incubation, silages were opened and analyzed for DM, Organic Matter (OM), Crude Protein (CP), Neutral Detergent Fiber (NDF), Acid Detergent Fiber (ADF), pH, lactic acid, acetic acid, propionic acid, butyric acid concentrations and in vitro DM Digestibility (IVDMD). The concentrations of DM, OM and NDF were higher, but CP concentration was lower in silages compared with hays (P<0.05). All silage pH were around recommended optimal pH value of 3.8-4.2, ranging from 4.09 to 4.20. Silage organic acid contents were generally in a desirable range (low in acetic and butyric acid and high in lactic acid content) and correlated with pH values. While IVDMD concentrations were higher (P<0.05), IVDMD yields were less (P<0.05) in hays compared with silages. However, CP yields were similar between two conservation methods. In conclusion, silage-making seemed to be the best conservation method for these sorghum-sudan grass varieties for eastern Anatolia conditions and hay making seemed to have great potential to yield more nutrient in places where it can be harvested more than 3 times, based on digestible DM yields and CP yields.