Evaluation of Stylosanthes scabra Accessions as Forage Source for Ruminants: Growth Performance, Nutritive Value and In Vitro Ruminal Fermentation

SIMPLE SUMMARY: Livestock production under smallholder farmers is limited by scarcity of good quality forage throughout the year. Therefore, there is a need to evaluate alternative forage crops to improve poor quality of the available forage source. Stylosanths scabra (Shrubby Stylo) is an important drought tolerant forage legume suitable for seasonally dry environments. It is a shrubby, erect legume with a long tap root system that make the species drought tolerant and able to produce moderate high quality forage under rain fed condition. Hence, Stylosanthes scabra is a good candidate species that need to be tested as an alternative forage source for smallholder farmers in tropical and subtropical climatic conditions often prone to drought and frost, owing to their biomass yield and nutritive value. ABSTRACT: Feed shortage is the main cause of poor production performance in livestock under smallholder farmer’s in South Africa. Therefore, this study evaluated the growth performance, nutritive value and in vitro ruminal fermentation of Stylosanthes scabra accessions in climatic condition of Pretoria, South Africa as potential forage sources in order to improve feed quality and subsequently livestock production. Stylosanthes scabra accessions were planted in 6 m(2) plots following a complete randomized block design with three replicates per accession. The plants were allowed to grow to full maturity after which forage was harvested and yield, chemical composition, phenolic compounds, in vitro organic matter digestibility (IVOMD) and in vitro ruminal fermentation characteristic were determined. Forage yield of accessions ranged between 4.3 to 5.3 t ha(−1) in dry matter (DM), and only twelve accessions were identified to be adaptable over the three-year evaluation under rain-fed. Accessions 140, 9281, 11,252, 11,595, 11,604 and 11,625 were consistent in terms of forage yield over the three years Significant differences among accessions were observed for crude protein (CP), neutral detergent fiber (NDF), IVOMD, metabolizable energy, metabolizable energy yield, gas production, total phenols, total hydrolysable tannins and total condensed tannins. Principal component and clustering analysis showed that accessions 11,255 and 11,625 are distinct in their characteristics as compared to the rest of the accessions, and both accessions are suitable forage source for animals since they contain low NDF with good forage production and crude protein content. However, there is a need for further study to integrate these accessions into the feeding systems in order to improve livestock production.