Effects Of Fatty Powder With Different Fatty A Cid Composition On Production Performance And Liver Function Of Dairy Cows

Under intensive production,the negative balance of postpartum energy of dairy cows often occurs,which seriously affects the milk production and health of dairy cows.Fat powder is a commonly used high-energy ruminant feed material.It contains high net energy value and has the characteristics of passing the rumen,which can avoid the adverse effects of fat on the activity of rumen microorganisms.Studies have shown that fat plays an important role in improving the performance of dairy cows,ensuring the health of dairy cows and increasing the economic benefits of dairy cow production.The purpose of this experiment is to study the effects of fat powder with different fatty acid composition on production performance and liver function of dairy cows,in order to provide a basis for the application of fat powder in dairy cows.160 healthy Holstein cows with basically the same lactation time(30～50 d),milk production and parity(2～4)were selected and randomly divided into 4 treatment groupswith 40 cows in each group.The control group received the TMR basal diet,while each cow in the trials 1,2 and 3 added 100 g/d of fat powder to the basal diet.Composition of three fatty acids A,B and C(Type A:79%palmitic acid,8%stearic acid,10%oleic acid and 3%linoleic acid;Type B:44%palmitic acid,5%stearic acid,40%oleic acid and 9.5%linoleic acid,coated;Type C:Palmitic acid content 98%,the rest are stearic acid,oleic acid and linoleic acid).The pre-period is 7 days,the trial period is 30 days.The result shows that:(1)Adding fat powder can effectively increase the average milk production of cows.During the entire trial period(0～30 days),the average milk production of the trial 1,2,and 3 groups increased by 10.57%(P<0.05),6.00%(P>0.05),3.80%(P>0.05),respectively,compared with the control group.(2)The addition of the Type A fat powder can increase the milk protein rate of dairy cows and reduce the lactose rate(P<0.05).(3)Adding fat powder to dairy cow diets can significantly increase the content of C14:0,C16:0,C18:1 and C18:2 in milk fat(P<0.05).The addition of the Type A fat powder can effectively increase the content of saturated fatty acids C14:0 and C1 6:0 in the milk fat of dairy cows,and the content of C1 8:1 and C1 8:2 in the trial 2 and 3 groups were higher than the control group.(4)Fat powder can improve the digestibility of CP and EE in the feed.(5)Fat powder composed of different fatty acids has a certain influence on liver function metabolism indexes.In the middle and late stages of the experiment(20～30 days),the effect of adding fat powder was obvious.The contents of serum ALP(P<0.05),TP(P>0.05)and Alb(P>0.05)of group 1 and group 2 were higher than those of the control group;The contents of serum AST and ALT in each group were significantly lower than those in the control group(P>0.05).(6)Adding fat powder with different fatty acid composition can effectively decrease the content of non-esterified fatty acids in dairy cow serum(P<0.05).The content of serum non-esterified fatty acid in trial 1 group was significantly lower than that in control group(P<0.05).There was no significant difference in serum BHBA acid content in each group(P>0.05).(7)The addition of fat powder has no significant effect on serum urea nitrogen,cholesterol and glucose content of dairy cows on the 10th day of the test.On the 20th day of the test,the serum urea nitrogen and cholesterol levels of each test group were lower than those of the control group(P>0.05).At the end of the experiment(30 days),the serum urea nitrogen and cholesterol content of the dairy cows in the 2 and 3 groups were significantly reduced after the addition of fat powder(P<0.05).In summary:Adding fat powder to dairy cow diets can increase milk production,improve milk quality,and alleviate negative energy balance of dairy cows in the early lactation period,and test group 1(Type A fat powder)has the best effect.