INFLUENCE OF WATER-SOLUBLE CARBOHYDRATE AND CRUDE PROTEIN CONTENT ON IN VITRO DIGESTION OF DRY MATTER IN HIGHLY DIGESTIBLE FORAGES
Freeze-dried samples from six series of harvests of orchardgrass (Dactylis glomerata L.) and two series of grass–legume mixtures were generally highly digestible with high levels of water-soluble carbohydrate (WSC). When WSC content was held constant, the influence of crude protein (CP) content on dry matter digested in vitro was statistically significant in 6 of the 19 cuts of orchardgrass and 1 of the 15 cuts of grass–legume mixtures. When CP was held constant, the influence of WSC content on dry matter digested in vitro was significant in seven cuts of orchardgrass and seven cuts of grass–legume. CP content had a greater effect than WSC content on dry matter digested in vitro in 10 cuts of orchardgrass and six cuts of grass–legume mixtures. Cumulative effect of CP and WSC content on in vitro dry matter digestion varied between cuts. The potential of CP and WSC content alone or together as predictors of digestibility of the highly digestible forages sampled in this study varied between cuts.