Studies On Ruminal Degredation And Intestinal Digestion Of Feed Constituents In Beef Cattle

The disappearance of dry matter (DM), organic matter (OM). crude protein (CP), (NDF) and (ADF) of 32 feedstuffs, fodder grasses and crop straws in rumen (from 2 to 72 h) were investigated using nylon bag (in situ). Intestinal polyenzyme (BIF) from beef cattle intestinal fluid was used to estimate the digestibilities of feedstuffs and ruminal undegraded CP and DM.Solutions presented in this thesis can be summarized as follows:The degradability of DM, OM, CP, NDF and ADF of feedstuffs increased with time in rumen. The part of slow degradability was higher than the part of fast degradability of feedstuffs. Compared with Animal feedstuffs were plant feedstuffs digested faster. The ruminal degradation of animal feeds in turn: Piru fish meal > fish meal (zhejiang) > meatmeal tankage > blood meal > feather meal; Plant protein feedstuffs: peanut meal > soy bean meal > sunflower meal > rape seed meal > cottonseed meal > flax meal; cereal feeds: barley > wheat > sorghum > corn >millet; grasses: alfalfa > autumnal grass > chinese wildrye; crop straws: corn silage > corn straw > soystraw > wheat straw > cotton straw > rice straw.Regression model and correlation of degradability between CP and OM in rumen were obtained. Regression model and significant correlation also existed between ruminal CP degradability and the contents of CP and ADF in original feedstuffsThe disappearance of DM, OM, CP, NDF and ADF in rumen was higher in daytime (8～20 h) than that in night (20～8 h.).The activity of trypsin and chymotrypsin in BIF depended on the kinds of cattle and feeds before slaughter.The digestibility of UDP with BIF was bond to be followed by incubation time in rumen.Amino-acids-profile in protein feedstuffs were not significant changed after incubation 12 and 24h in rumen and digestion with BIF.The degradability of total AA > necessary AA > branched AA in rumen and with BIF.