Relationship between In vivo, parameters and chemical composition to predict the nutritive value of some legume forages

Many in vivo and laboratory methods have been used to evaluate ruminant feeds. The objective of this experiment was to determine feed intake, digestibility, kinetics of gas production, in vitro organic matter digestibility (OMDv) and metabolizable energy (ME) of Trifolium alexandrinum (T. alexandrinum) and Medicago sativa (M. sativa) at different maturity stages through in vivo and in vitro methods to elaborate predictive equations from chemical constituents.

Methods: In vivo assay was carried out with two groups of five rams male kipped in metabolism cage. Samples of forage, refusal and feces were collected and processed for chemical analysis. In vitro gaz production technique was performed on forage samples.

The bud and early bloom stage of M. sativa recorded the highest digestibility values of the chemical component (P<0.05). The OMDv of M. sativa was 60.65 and 68.26% (P<0.01) for early bloom stage and bud stage, respectively. Crude protein digestibility (CPD) was positively correlated with crude protein rate (R²=0.83, P<0.05). The gas production from the insoluble fraction “b” fraction showed a positive correlation with acid detergent fiber (ADF) (R²=0.999, P<0.001). However, cumulative gas production at 24 h and 48 h of incubation were negatively correlated (P<0.05) with the ADF rate (R²= -0.98 and -0.97, respectively).