Study On Predicting Model Of The Absorbed Amino Acid Fluxes In The Small Intestine Of Milking Cow

Carbohydrate and protein fractions and their digestion rates of cow feed in shandong province were determined in this study based on the method in cornell net carbohydrate and protein system model(CNCPS).Besides, we find there have something to be improved in cornell net carbohydrate and protein system.Then we modified the model in some aspects.Experiment part one: Study on digestibility kinesics protein in rumen and Predictive model of rumen undegraded protein.Studies were conducted with three healthy dairy cows with permanent rumen cannulas, conform milk yield and lactation in initial stages.fifteen cow feedstuff nutritional values were evaluated with rumen nylon bag method.Besides this trail determin the ratio of every protein fractions and ruminal degradation rates of protein fractions of B1,B2 and B3 of 15 feedstuffs for dairy cow. Througe this experiment,we developed an predictive method of ruminal degradation rates of every protein fractions.Experiment part two: Study on digestibility kinesics of ruminal undegraded protein in small intestine and predictive model of small intestine absorbable proteinA pepsin-pancreatin in vitro method using dialysis tube was studied to measure digestibility value of the residues after rumen.and small intestine digestibility of every protein fractions were predict ed with an curve fitting system. The results indicated that the predicitive values of protein fractions of B1,B2 and B3 were same as the values which CNCPS were used. Througe the experent ,we found that protein faction C coule be digestied in some feedstuff of the fifteen feedstuff ,but in In cornell net carbohydrate and protein system model, faction C was be thought coule not be digestied by cows .So a more mechanistic approach is needed predict intestinal digestion of the residues after rumen.Experiment part three: study on amino acid composition of every protein fractionsIn cornell net carbohydrate and protein system model,same essential amino acid composition of protein fractions B1,B2and B3 is used to calculate supply of amino acid of RUP. This trial determined amino acid composition of protein fractions B1,B2,B3andC,great differences were found among these protein fractions.These differences woule serious influence the accuracy of the model. A more mechanistic approach is needed to take palace the approach of cornell net carbohydrate and protein system.