The Effects Of Composite Feed Additives On Nutrient Digestion,Blood Biochemical Index And Milking Performance In Dairy Cows

The purpose of this experiment was to investigate the effects of composite feed additives on nutrient digestion,blood biochemical index and milking performance in dairy cows,so as to achieve the purpose of high absorption,low excretion and reducing the pollution of excreta.This experiment was a single factor design,Twenty-four Holstein dairy cows with same parity,in middle and late lactation were randomly divided into 4 groups according to the gradient of 2times additive as control group(compound feed was 0.00 g/d),trial group A(compound feed was 113.50 g/d),trial group B(compound feed was 227.00 g/d),trial group C(compound feed was 454.00 g/d).There were 6 replicates in each group for 30 day.The result showed that:(1)Different doses of composite feed additives have no significant effect on the dry matter,and the apparent digestibility of the calcium and phosphorus of dairy cows in each period(P>0.05).The apparent digestibility of organic matter in dairy cattlecow were significant between group A and treatment group at 0 d and 30 d(P<0.05),In the treatment group,group C was increased during experimental stage.The apparent digestibility of crude protein in the whole trial group was higher than that in the control group A,but there were no significant(P>0.05);At10 d,the apparent digestibility of fat in group D was significantly higher than that of group A(P<0.05).In apparent digestibility of neutral detergent fiber and acid detergent fiber,group C was significantly higher then group A and B at 0 d(P<0.05),and also significantly higher then other three group at 20 d(P<0.05);the neutral detergent fiber in group C was also significantly higher then other three group at 10 d(P<0.05).Different did of composite feed additives had no significant effect on dry protein,crude fat,acid detergent fiber and phosphorus excretion from dairy cows(P>0.05).The excretion of neutral washing fiber in group D was significantly lower than that in group A and C(P<0.05).The amount of neutral detergent fiber in group C was decreased al the time.In group C,the calcium excretion in dairy cows was significantly higher then group A at 0 d(P<0.05).(2)Different doses of composite feed additives have no significant effect on serum albumin,urea nitrogen,triglyceride,cholesterol and glucose blood,glutamic oxalacetic transaminase,alanine aminotransferase,creatinine kinase,calcium and phosphorus(P>0.05).After 10 d,Total protein content in serum in treatment group were significantly higher then group A(P<0.05).The blood phosphorus content in the group C were increased with the test period.In the change of amino acids,there were no significantly effect between treatment group and control group(P>0.05),except free leucine in serum which was significantly higher in control group A then that in treatment group at 30 d(P<0.05).(3)The effect of different dosage of composite feed additives on milk yield of dairy cow was not significant,but compared with the control group A,the milk yield of treatment group showed an increasing trend with the prolongation of the trial period,and group C was the best.In the dairy milk quality,group C was increased with the prolongation of the test period.The urea nitrogen content in the milk in treatment group was lower than that in the control group A which were significantly at 30 d.There was no significant difference in the number of somatic cells between group A and treatment group(P>0.05),and It was within the normal range.The effect of composite feed additives on milk taste,smell,color,thickness and sensory evaluation was no significant(P>0.05).In conclusion,the composite feed additives had improved effectively the digestibility of feed,reduced the degree of environmental pollution of the nutrients in the excreta,improve the total protein content in serum and increase the milk yield and milk quality.the group C had the best effect.