Effects Of Supplemental Rumen-Protected Methionine On Production Performance,Nutrient Digestibility And Serum Parameters Of Lactation Cow

With the development of animal husbandry,the requirements of milk yield and quality of dairy cows are gradually improved.Therefore,more and more attentions are paid to the protein levels and quality of dairy cows’ diet in production.China is a country with extreme lack of protein,amino acid balanced diet is an effective means to make up for the lack of protein feed.In this experiment,the effect of rumen protective methionine on the relevant indicators of lactating dairy cow is studied,in order to provide a theoretical basis for the promotion of amino acid balance diet in dairy cows.40 Holstein multiparous lactating cow with similar day in milk,production performance and body condition sore were selected,and randomly divided them into 2 groups.The control group was fed the basic diet,and the trail group supplemented HMBi(lysine% MP : methionine% MP =2.8:1)according to the dietary 0.127% DM on the basis of the control group,and the other nutrients were consistent.The pre-trial period is 7 d,the trial period is 60 d.The main findings are as follows:1.The effects of lactation diet supplemented with rumen-protected methionine on production performance,milk contents on lactation cow.There was significant difference in average milk yield of the lactating dairy cow in each treatment group(P<0.05);There was no significant difference in weekly milk yield of the lactating dairy cow in each treatment group(P>0.05);And at the fiftieth day,there was significant difference in milk fat content of the lactating dairy cow in each treatment group(P<0.05);In terms of the milk protein content,MUN,milk fat yield,milk protein yield,milk somatic cell counts were not significantly different in each treatment group(P>0.05).The results showed that supplementation of rumen-protected methionine in lactating dairy cow diets under the conditions of this experiment could significantly improve milk yield and milk fat content,but had no significant effects on milk protein content,milk protein yield,milk fat yield,MUN and somatic cells of lactating cows.2.The effect of lactation diet supplemented with rumen-protected methionine on serum parameters,antioxidant indexes,inflammation indexes in lactating dairy cow.There was no significant difference in serum concentrations of Total Protein(TP),Globin(GLB),Albumin(ALB),Alanine Aminotransferase(ALT),Aspartate Aminotransferase(AST),Blood Urea Nitrogen(BUN),Total Cholesterol(TC),Alkaline Phosphatase(ALP),Lactic Dehydrogenase(LDH)among the trail groups(P>0.05).There was no significant difference among the trail groups in the Interleukin-6(IL-6)and Haptoglobin(Hp)(P>0.05).There was no significant difference among the trail groups in the Superoxide dismutase(SOD),Malondialdehyde(MDA),Total Antioxidant Capacity(T-AOC),Catalase(CAT),and Glutathione Peroxidase(GSH-PX)(P>0.05)。The results showed that supplementation of rumen-protected methionine in lactation diets under the conditions of this experiment would not affect the serum parameters,antioxidant indexes and inflammation indexes.3.The effect of lactation diet supplemented with rumen-protected methionine on nutrient digestibility in lactating dairy cow.There was significant difference in apparent nutrient digestibility of the Crude Protein(CP)and Neutral Detergent Fiber(NDF)in each treatment group(P<0.05);There was no significant difference in apparent nutrient digestibility of the Ether Extract(EE),Acid Detergent Fiber(ADF),Dry Matter(DM),Organic Matter(OM)in each treatment group(P>0.05).The results showed that supplementation of rumen-protected methionine in lactating dairy cow diets under the conditions of this experiment could significantly improve apparent nutrient digestibility of CP and NDF,but had no significant effects on apparent nutrient digestibility of EE,ADF,DM and OM.In summary,after supplementing the rumen-protected methionine can increase milk yield and milk fat content,and increase the apparent nutrient digestibility of crude protein and neutral detergent fiber in the diet,indicating the feasibility of supplementing rumen methionine in lactating dairy cows.