The effect of dietary protein and energy supplementation on in vitro-rumen characteristics and digestibility of Bali bulls

The aim of this study was to measure the effect of dietary protein and energy supplementation on rumen characteristics and digestibility of Bali bulls, by in vitro. Leucaena leucocephala (LL) and Corypha elata Robx (CeR) as protein and energy sources, respectively, and Native Grasses (NG) collected from Natural Pasture (NP) in Timor-Leste, were used as dietary treatments. A 3 x 3 factorial design was used in this study, namely, protein and energy sources (LL, CeR and LL-CeR) and 3 levels of supplementation (10, 15 and 20). Rumen characteristics (pH, NH₃, microbial protein (MP), and volatile fatty acids (VFA) production and composition) and dry matter (DM) and organic matter (OM) digestibility were measured. We found that dietary supplementation had a significant (P<0.05) effect on rumen characteristics in terms NH₃ concentration, total VFA, acetic acid, propionic acid) but did not affect the pH, butyric acid and microbial protein (P>0.05). The digestibility of DM and OM were also significantly increased (P<0.05). It is concluded that dietary supplementation improves rumen characteristics and digestibility of Bali bulls. Leucaena Leococephala and CeR are recommended as protein and energy supplementation, respectively, on NG diet in NP in Timor-Leste to optimize productivity of Bali cattle.