Effect of growth stage and method of conservation of H. filipendula and H. dissoluta on nutrient composition and digestibility

Abstract

Native species such Hyparrhenia filipendula and Hyperthelia dissoluta have great potential in livestock production but not much has been done to improve their contribution to that sector. This factorial study examined 2 grass species (H. filipendula and H. dissoluta) × 2 conservation methods (drying and ensiling) × 3 different growth stages, namely: elongation stage (January), early flowering (February) and late flowering stage (March) of H. filipendula and H. dissoluta during growing season in terms of nutritional composition and digestibility. There was no difference (P>0.05) in nutritional composition between the two-grass species. The method of conservation had an effect (P<0.05) on nutritive value, with silage having more phosphorus (P), neutral detergent fibre (NDF) and crude protein (CP) than hay. Stage of growth had an effect (P<0.05) on all nutritional properties of both hay and silage. Phosphorus, Calcium, NDF, CP concentrations and digestibility of hay and silage decreased with maturity, while acid detergent fibre (ADF) concentration increased. Silage pH value was significantly higher at elongation 5.1 and 4.9 for H. filipendula and H. dissoluta, respectively. Silage pH for early flowering stage was within the recommended ranges from 4.1 to 4.4 on the pH scale, with higher than the recommended range for the late flowering growth stages (4.8 and 4.5) for H. filipendula and H. dissoluta, respectively. Dry matter digestibility of the conserved material reached levels as high as 80% for silage made at the elongation stage with all values at least 60%. The study results reveal that H. filipendula and H. dissoluta can be conserved as both silage and hay to produce a good quality feed. Harvesting at the early flowering stage provide a good compromise between quantity and quality of harvested forage. Further studies are necessary to assess the acceptability of the forage by livestock as well as to determine dry matter yields in different areas and a range of seasonal conditions.