Effects of rice straw basic diet supplemented with varying level of alfalfa hay on nutrients digestibility in different segments of digestive tract for goat

Nine healthy and half sib Chengdu Ma Goats with similar weights (41.3±1.2) kg and fitted with permanent cannulas in the rumen, the proximal duodenum and terminal ileum were randomly divided into three groups and fed the different diet which was rice straw (RS) supplemented with 25% (MSL25), 50% (MSL50) and 75% (MSL75) alfalfa hay (Medicago sativa, MSL), respectively. The nutrients digestibility in different segments of goat digestive tracts were determined with Co-EDTA as markers. Gastric dry matter (DM) digestibility (%), small intestinal DM digestibility (%), large intestinal DM digestibility (%) and gastrointestinal DM digestibility (%) for MSL25, MSL50 and MSL75 were 37.70%, 40.44% and 41.57%, 5.30%, 5.61% and 7.27%, 17.15%, 19.03% and 24.20%, 51.12%, 54.48% and 58.92%, respectively. The organic matter (OM) digestibility (%) were 41.18%, 44.83% and 45.70%, 5.45%, 5.94% and 7.77%, 18.18%, 20.62% and 26.12%, 54.49%, 58.81% and 62.96%, respectively. The neutral detergent fiber (NDF) digestibility (%) were 39.97%, 42.24% and 43.19%, 3.58%, 2.69% and 4.61%, 6.61%, 7.47% and 11.52%, 46.46%, 48.00% and 52.05% respectively. Gastric acid detergent fiber (ADF) digestibility (%), posterior ADF digestibility(%) and gastrointestinal ADF digestibility(%) for MSL25, MSL50 and MSL75 were 38.81%, 44.52% and 48.61%, 1.29%, 5.28% and 4.71%, 39.59%, 47.45% and 51.05% respectively. It is concluded that goats RS basic diets supplemented with 25%~50% in this experiments could not only improve the RS fiber fermentation in gastric area, but also improve the RS fiber digestibility in lower digestive tract, therefore increase the fiber digestibility in whole digestive tract.