Effect Of Rumen Protected Methionine On Milk Performance And Blood Index Of Milk Goat

Methionine,as the first or second limiting amino acid in ruminants,which has a significant effect on the maintenance of animal growth and development and physiological activities in ruminants.There are few researches on the effect of rumen protected methionine on milk goat production and blood indexes at home and abroad,and the appropriate protective method and adding level of rumen protected methionine are not clear.IIn the first experiment,rumen protected methionine was added with different protective methods to the diet,and the aim was to select the rumen protected methionine with better method for protection to enhance the production efficiency of milk goats.According to the results of the test one,different levels of rumen protected methionine in the diet is added in the second experiment to select proper level and improve the production efficiency of milk goats,which provided a theoretical basis for the nutritional regulation of milk goats.The purpose of the first experiment was to study the effect of different protective method of rumen protected methionine on milk yield and blood index of milk goat in diet.A completely randomized trial design was adopted to select 45 Guanzhong milk goats with similar weight(52.6kg±4.9kg),similar fetal times and similar lactation age(120d±10d),randomly divided into 3 groups with 15 duplicates per group.The control group did not add rumen protected methionine,the trial I group was added the rumen protected methionine A 4.5g/d,the trial II group was added the rumen protected methionine B 4.5g/d.In the total test period of 39 days,9 days are in the pre-test period and 30 days are in the trial period.The results are showed as follows: 1)the milk-feed ratio of trial I group and trial II group was significantly higher than control group(P<0.01),the milk income and gross returns were higher than control group(P>0.05).2)The milk fat of trial groups were higher than control group.The trial I group?the trial ? group was 6.75% and 13.18% higher than the control group.The trial ? group,s milk protein was higher than the control group(P>0.05);3)Two trial groups serum total cholesterol and urea nitrogen were lower than the control group(P>0.05),and the IgG of the trial ? group was higher than other groups(P<0.05).To sum up,adding rumen protected methionine A and B can improve the milk-feed ratio and economic benefits.Rumen protected methionine A can improve body immunity,rumen protected methionine B can improve the quality of milk.The second experiment was study to the effect of adding different levels of rumen protected methionine on milk performance and blood index of milk goat.75 Guanzhong milk goats with similar conditions in the first experiment were randomly divided into 5 groups with 15 duplicates per group.The supplement level of rumen protected methionine B in control group and test groups was 0,1.5,3,4.5,6g /(d·head),respectively.The pre-test period is 9 days,the trial period is 30 days,and the total test period is 39 days.The results showed as follows: 1)Diet added 6g/d rumen protected methionine can significantly improve milk protein,SNF,serum immunoglobulin G(P<0.05),and significantly increase the content of free amino acids(P<0.01).To sum up,the diet added 1.5g/d rumen protected methionine B can improve the economic benefit,and the diet added 6g/d rumen protected methionine B can improve the quality of goat milk and immunity in lactating period.