Effect Of NDF Levels Of Supplementing Feed On Digestive Tract Development Of Lambs

24male Hu lambs were divided to4groups (no supplementary feeding, high NDF,middle NDF and low NDF) to research the effect of NDF levels of supplementing feed ondigestive tract development. All lambs were slaughtered at35days. Weight and Volume ofthe digestive tract, the length of each part of the intestine and the rumen fermentationparameters were determined.The results showed that:(1) The body weight, average daily gain and the carcassweight of high NDF group were significantly higher than no supplementary feedinggroup(P<0.05), and the carcass weight of high-NDF group significantly higher than lowNDF group (P<0.05).(2) The relative rumen weight (%body weight,%total digestive tractweight and%total stomach weight) of high NDF, middle NDF and low NDF groups weresignificantly higher than no supplementary feeding group (P<0.05), the relative volume (%total alimentary tract volume,%full stomach volume) has similar trends too (P>0.05).Theabomasum weight of high NDF, middle NDF and low NDF groups were higher than nosupplementary feeding group(P>0.05), but the relative weight and relative volume were justthe opposite(P>0.05).(3) The jejunum relative weigh（t%body weight）of high, medium andlow NDF were significantly higher than no supplementary feeding group (P<0.05). Cecumrelative weight (%total intestinal tract) of low NDF group was significantly higher than thatof high and middle NDF group (P<0.05).(4) Ruminal pH of no supplementary feedinggroup was6.74，significantly higher than supplementary feeding group (P <0.05). There areno significant differences of PH between high, middle and low NDF group (P>0.05).(5)Total VFA concentration of no supplementary feeding group was significantly lower thanother groups and the acetic molar ratio was the highest at69.37%, propionic and butyricmolar ratio was the lowest. Acetic molar ratio of high NDF group has the higher tendencythan low NDF group (P <0.1). Butyric mole ratio of Middle NDF and low NDF group washighly significantly higher than that of no supplementary feeding group (P <0.01) andbutyric mole ratio of high NDF group was significantly higher than that of nosupplementary feeding (P<0.05). The ratio of acetic to propionic acid of treatment groupswere highly significantly lower than that of no supplementary feeding group (P <0.01).(3)Ruminal urea nitrogen content of low NDF group was very significantly higher than that of other groups (P<0.01), urea nitrogen content of high NDF and middle groups wassignificantly higher than that of no supplementary feeding group (P<0.05). Ruminalammonia nitrogen content of no supplementary feeding group was very significantly lowerthan other groups(P<0.01). Ruminal total nitrogen content of low NDF group was verysignificantly higher than that of other groups, high NDF and middle NDF group was verysignificantly higher than that of no supplementary group.Comparing all quotas, the growing performance of high NDF group was the best. Theeffect of supplementary feeding on rumen development was more apparent than otherstomach development. The NDF level had greater impact on alimentary tract relative qualitythan the relative volume.