Evaluation Of Nutritional Value Of Different Diets For Dairy Cow

In the experiment, three Total Mixed Rations (TMR) according to large-scale dairy farm, standardized dairy cow raising area and the free-range farmers were be researched. Diet MF (Mixed Forage) was the TMR usually used in Large-scale dairy farm, Roughage was made up of alfalfa and silage; Diets CSA (Corn Straw A) was the TMR,which used corn straw to replacing for the alfalfa and corn silage in the MF; Diet CSB (Corn Straw B) used mixed meal replacing for soybean meals in the diet CSA. In order to evaluate nutritional value of common diets for diary cow in China, CNCPS system, rumen nylon bag method, feeding and digestibility trials were used to evaluate the nutritional value of three diets, and combining with production, discusses different types of diet affect the performance of dairy cattle nutrient digestibility and production. Test consisted three parts:Experiment1:The experiment evaluated nutritional value of common feed and different diets for diary cow according to Cornell Net Carbohydrate and Protein System.The results showed that:CNCPS analysis method could determine more indicators and react comprehensively nutrients of feed and feed utilization of animal. Using straw instead of alfalfa silage as roughage source of diet decreased the of content CP and energy in TMR, increased the carbohydrate (CHO), but at the same time reduced the CNSC and PC of protein in rumen. With miscellaneous meal replacement diet puffing soybean meal and soybean, further reducing the diet of CP and energy level, increase the indigestible carbohydrates components CC and PC of protein.Experiment2:The experiment was carried out on three fistulated multiparous Holstein dairy cows to research ruminal degradation of nutritions of different diets using nylon bag technique,and calculated the rumen energy nitrogen balance(RENB). The results showed that:using com straw instead of alfalfa and corn silage in the diet MF, reduced rumen degradation rate of DM, OM, CP, NDF and ADF; There was not significant difference of rumen effective degradation rate of each nutrition, when uesd miscellaneous meal instead of soybean meal group. MF and CSA groups were in a negative balance of nitrogen, the CSB was in a positive balance of nitrogen.Experiment3:48Holstein cows with similar weight, parity and DIM were chosed to determine the digestibility of the diets and performance of the cows, cows were randomly assigned to3groups,and were fed3diets respectively. The results showed that:using corn straw instead of alfalfa and corn silage in the diet MF reduced apparent digestibility of nutrients of diet, DMI,milk yield, protein percetage, protein yield and fat yield sigenificantly, but has no effect on fat percentage; Using miscellaneous meal instead of soybean meal reduced nutrition level of diet, increased th digestibility of diet significant1, but had no effect on production performance.