Study On The Correlation Between Rumen Dynamic Degradation Parameters And Nutrient Content Of Four Kinds Forages Commonly Used In Dairy Cows

In this experiment,the correlation between nutrient content and rumen dynamic degradation parameters of four kinds of common roughages for dairy cows,including Leymus chinensis,corn silage,alfalfa hay and oat grass,was analyzed,and the regression relationship between them was established.The significance is that the determination of nutrient content can calculate the rumen dynamic degradation parameters of roughages,more accurately understand the nutritional value of roughages,and improve the accuracy of dairy diets.Three lactating Holstein cows weighing about 700 kg and fitted with permanent rumen fistula were selected as experimental animals.The disappearance rates of DM,CP,ADF,NDF and other nutrients in rumen of different quality samples of Leymus chinensis,corn silage,alfalfa hay,and oat grass were determined by nylon bag method(in situ method).The degradation kinetic parameters of each sample were calculated according to the feed degradation model,and then the regression analysis was conducted between the degradation kinetic parameters and nutrient content.The results showed that when there were significant differences in DM,CP,ADF and NDF among different samples of the same variety,the rumen disappearance rates of DM,CP,ADF and NDF among different samples were significantly different(P <0.05),and the rumen dynamic degradation parameters were also different.Nutrient content of feed ingredients will affect the dynamic degradation parameters of feed ingredients in the rumen.The rumen dynamic degradation parameters of Leymus chinensis,alfalfa hay and oat grass are mainly affected by the contents of CP,ADF and NDF.The rumen dynamic degradation parameters of corn silage are mainly affected by the contents of CP,ADF,NDF and Starch.The relationship between the two can be expressed by regression equation.