Effects Of Concentrate Supplementation On Growth Performance,Blood Indices And Rumen Fermentation Of Growing Cattle Under Grazing Condition

Beef cattle is an important part of modern agricultural economic animals,and their breeding methods are mainly grazing,house feeding and semi-grazing.The advantages of beef cattle grazing and fattening are the full use of natural resources and low feeding cost.However,the advantages and disadvantages of grassland natural resources are different,and the overall growth performance of beef cattle is greatly affected by the environment.The purpose of this experiment was to study the effect of concentrate supplementation on the growth of beef cattle in the growing period under traditional grazing.The natural grassland in Alukeerqin Banner of Inner Mongolia Autonomous Region was used as the grazing test field for beef cattle,and 18 weaned Simmental male cattle were randomly selected as the test subjects.Cattle in the control group did not change any conditions and were grazed and raised freely all day long.Cattle in experimental group were supplemented with a certain amount of concentrate every day according to the nutritional requirements of beef cattle.The effects of supplementary feeding on growth performance and physiological indexes of growing cattle were studied,and the effects of supplementary feeding on growth and development of beef cattle were analyzed from the perspectives of nutrition metabolism.This experiment was divided into four parts.The effects of concentrate supplementation on the growth performance,blood indexes,blood amino acid metabolism and rumen fermentation level of adult cattle were analyzed respectively.To provide scientific basis for promoting the early growth and development of mature cattle and improving the efficiency of shelf cattle.The results showed as follows: body weight,body slant length,body high growth and average daily gain of adult cattle fed with concentrate were significantly higher than those in grazing group(P<0.05).The blood glucose concentration in supplementary feeding group was higher than that in grazing group,but the difference was not significant(P>0.05),and the serum total protein content was extremely significantly higher than that in grazing group(P<0.01).The contents of blood growth hormone(GH),thyroid hormone(T4)and insulin(INS)in supplemental feeding group were significantly higher than those in grazing group(P<0.01).The activities of serum alkaline phosphatase(ALP),fatty acid synthase(FAS)and Acetyl-coenzyme carboxylase(ACC)in supplemental group were significantly higher than those in control group(P<0.05).The antioxidant levels in supplementary feeding groups were extremely significantly higher than those in grazing group(P<0.01),but there were no significant differences in immune indices between the two groups(P>0.05).The content of total amino acids in blood in supplementary feeding group was significantly higher than that in grazing group(P<0.05),and the ratio of essential amino acids(EAA)to total amino acids in supplemental feeding group was higher than that in grazing group.Serum common restricted amino acids such as lysine and methionine in grazing group were higher than those in grazing group,and the content of functional amino acids(FAA)in grazing group was extremely significantly higher than that in grazing group(P<0.01).Concentrate supplementation increased the proportion of propionic acid fermentation in rumen contents,and the decrease of ammonia nitrogen level increased the rumen metabolic rate and the ability of bacterial protein synthesis in beef cattle.The p H value of rumen fluid decreased within a certain range but not beyond the normal range,which indicated that supplemental feeding with this area would not have harmful effects on beef cattle,and was an effective way to make full use of natural resources and ensure and improve the growth performance and fattening potential of growing beef cattle.