Occurrence of digestive interactions in tree forage-based diets for sheep

The effect of browse level in the diet on the in vivo dry matter digestibility (DMD) in sheep and the DM degradation of peanut hay in the rumen of cattle-fed tree forage-based diets were investigated in order to detect the occurrence of digestive interactions between diet components. Selected browse species Acacia albida pods, Pithecellobium dulce, Adansonia digitata and Calotropis procera leaf samples were collected in the central regions of Senegal, sundried and stored in LNERV animal barns for in vivo trials. Classical in vivo balance trials were performed for each tree forage sample. The proportion of browse in the applied diet varied between 0 and 75% of DM. Regression and difference procedures were both tested to estimate the DIVID of the browse component of the diet. DMD capacity in the rumen of three young Gobra bulls fed the browsebased diets was estimated by measurement of the in sacco dry matter degradation profile of a standard sample, peanut hay. For each sample, large variations were observed when the browse DMD was calculated by difference. Both total ration DIVID and rumen DM degradation capacity were significantly (p<0.001) influenced by browse level in the diet. However, non-linear response of total diet DMD to increasing levels of browse was observed only in A. digitata and P dulce indicating occurrence of digestive interactions in those species