Evaluation On Nutritional Value Of Common Feed Resources And Roughage Combination Effect Of Cashmere Goats By In Vitro Three-step Method

The nutritional value of feed raw materials plays an important role in optimizing feed formulas and formulating animal diet plans,and there are still few studies on the nutritional value assessment of feed raw materials commonly used by cashmere goats.This thesis evaluates the combined effect of the nutritional value and roughage resources of cashmere goats by studying the degradation rate of in vitro nutrients and the parameters of rumen fermentation in vitro of commonly used feed raw materials by in vitro three-step method(rumen juice method-pepsin-pancreatic enzyme),and provides a basis for the establishment and improvement of cashmere goat feed database.The test is divided into 3parts:Experiment 1 used a one-way completely randomized trial design,through the in vitro three-step method,to compare the nutrient degradation rates of nutrients in 6 roughages(corn straw,grain grass,alfalfa,corn silage,oat grass,sheep grass)and 16 refined feeds(corn,tableted corn,wheat,secondary flour,wheat bran,corn husk,corn germ meal,spray protein,soybean skin,soybean meal,cotton meal,corn protein powder,double low rape meal,rape meal,puffed soybean,DDGS).Feed raw materials were continuously cultivated in vitro to simulate the rumen environment(roughage for 48 h,refined feed for 24h),simulated digestion of the gastric environment for 1h,and simulated digestion of the small intestine environment for 24 h.The results showed that in the roughage,the degradation rate of rumen-gastric-small intestine in vitro multiple nutrients of cashmere goat to alfalfa and corn silage was higher than that of other roughages to varying degrees,among which the degradation rates of DM,OM,CP and EE were above 96%-98%,94%-96%,97% and88%,respectively,de was higher than 16MJ/kg,and the degradation rate of NDF,ADF and HCL in the in vitro rumen was higher,and its nutritional value was higher than that of corn straw,grain grass,oat grass and sheep grass.In the refined feed,the rumen-gastric-small intestine in vitro nutrient degradation rate and DE of the cashmere goat on corn,tableted corn and soybean meal were higher than those of other refined feeds to varying degrees,among which the degradation rates of DM,OM,CP and EE were above 93%,89%-100%,89%-100% and 95%,respectively,and the DE was higher than 15MJ/kg,but the EE degradation rate of soybean meal was low,66.41%.The degradation rate of rumen-gastric-small intestine in vitro nutrients and DE of corn husk and soybean husk of cashmere goats was lower than that of other refined feeds to varying degrees,and the degradation rates of NDF,ADF and HCL in vitro rumen were also lower than those of other refined feeds.Corn,flapped corn and soybean meal have higher nutritional value,while corn husks and soybean husks are lower.For the degradation contribution rate of refined feed nutrients in the in vitro rumen of cashmere goats,in addition to spray corn meal,cotton meal and corn,the degradation contribution rate of DM and OM are mostly above 70%;CP degradation contribution rate is higher than 80% in rapeseed meal,wheat,secondary flour and wheat bran,and DDGS,corn germ meal,corn,corn husk and puffed soybeans are lower,all below 50%;EE degradation contribution rate is higher in rapeseed meal and flaped corn,more than 85%,and corn germ meal and soybean meal are lower,below 50%.For roughage,dm,OM,CP and EE of alfalfa,maize silage contributed mostly to more than 70% of the rumen in vitro of cashmere goats,corn stalks were the lowest,all below 65%,and OM and EE degradation contributions of grain grasses were less than 60%.Experiment 2 adopted a one-way completely randomized trial design,and compared the rumen fermentation parameters of the above six roughages by in vitro three-step method,and each feed was treated as a treatment,with corn stalks as the control group.The results showed that the p H of rumen in vitro was the highest in alfalfa and the lowest in corn silage,and the BCP concentration was higher in alfalfa grass,corn silage and oat grass,especially alfalfa grass,corn straw was the lowest,and the in vitro rumen NH3-N concentration was the highest in corn silage,the lowest corn straw,and the grass was also lower.The number of protozoa is highest in corn silage and lowest in alfalfa.Different roughage in vitro rumen culture fluids TVFA concentrations were higher in maize silage and alfalfa,and corn stalks and lowest;gas yields were higher in maize silage and alfalfa grass,and corn stalks and millet grasses were lower.Among the multiple combined effect values of different roughages,the MFAEI values of maize silage and alfalfa were larger,followed by grain grass,and corn stalks were the lowest.Cashmere goats have a good rumen fermentation effect in vitro for corn silage and alfalfa,and corn stalks and grain grasses are poor.Experiment 3 adopted the one-factor complete randomized trial design of the experiment,and determined the nutrient degradation rate and rumen fermentation parameters of different roughage combinations by in vitro three-step method,with a total of 5 treatment groups and 6 replicates per treatment group.Among them,corn straw was the control group(CON group),and the I,II,III,IV and V groups were replaced by alfalfa,grain grass,corn silage,oat grass,sheep grass and other proportions of 20% corn straw to form a new roughage combination group.Each treatment group was continuously cultured in vitro for 48 h with 6 replicates per treatment group.The in vitro nutrient degradation rate and rumen fermentation index in vitro were compared with each group.Studies have shown that in different roughage combinations,the substitution of 20% of corn stalks with alfalfa,corn silage,sheep grass,oat grass and grain grass produces different combination effects,and the combined DM,OM,CP and EE in vitro rumen-gastroenterol degradation rate and in vitro rumen degradation rate are mostly better than that of the CON group,of which the corn silage combination is better.Among the multiple combined effect values of different roughage combinations,the MFAEI value of group I was larger,followed by group III,IV group and V group,and group II was the lowest,But both are higher than the CON group.Alfalfa and corn silage had a better combination effect after publishing substitution of 20% of corn stalks,followed by sheep grass and oat grass,and worst in the grain grass substitution group.In summary,the nutritional value of alfalfa and corn silage in the roughage was higher,the nutritional value of corn,flapped corn and soybean meal in the refined feed was higher,and the corn husk and soybean husk were lower;with corn stalks as the control,the proportion of alfalfa,grain grass,corn silage,oat grass,sheep grass and other proportions replaced by 20% corn stalks for different combinations,all of which produced a positive combination effect,especially the combination effect of alfalfa and corn silage substitution group was better.