Effects Of The Different Doses Of Rumen Protected Betaine On Milk Production And Serum Parameters And Hsp70mRNA Level Of Dairy Cows In Heat Stress

The aim of the experiment was analysis the effect of different dose of rumen protected betaine on milk production and serum parameters and Hsp70mRNA level of dairy cows in heat stress to provide information for the use of rumen protected betaine in dairy cows.Experiment one:The subject of this experiment studied the effect of rumen protected betaine on milk production in holstein dairy cows.Thiry-six holstein dairy cows were randomly divided into three groups according to the age,stage of lactation and milk yield.The three groups respective were basic control (add to10g/d rumen protected betaine in TMR),treatment I (add to20g/d rumen protected betaine) and treatment II (add to30g/d rumen protected betaine).The results showed that the average of THI in cowhouse was83.28.The average of RT were over39.6℃.We found a decline tendency with the incremental dose of rumen protected betaine.It is not difference of milk yield and milk composition among treatment Ⅰ and Ⅱ than that of basic control.But there are0.58kg/d in treatment I and1.17kg/d of milk yield higher in treatment Ⅱ than basic control.There are no significant difference of milk composition between basic control and treatments.The results showed that Holstein dairy cows were middle stress and30g/d rumen protected betaine in TMR is better for lactating cow production.Experiment two:The design of experiment was the same as experiment one.The blood samples were collected from caudal vein with ACD in the tube in the day before the test,the21st testing day and the47th testing day.The blood plasma were storaged below-20℃to analysis the level of Glu,CPK,ALP,LDH,TP,ALB,BUN,SOD,GSH-Px,MDA,Cor,T3and T4.The results showed that the level of Cor in treatment II was lower than basic control(P>0.05) and treatment Ⅰ (P<0.05) in the21st testing day.The level of T4in treatment Ⅱ was lower basic control(P<0.05) and treatment I (P>0.05) in the47th testing day.The level of Cor and T3in treatment Ⅰ and Ⅱ and were lower than that of basic control(P>0.05).The level of GSH-Px in treatment Ⅱ was higher than basic control (P<0.05) and treatment I (P>0.05) in the21st testing day.The levels of GSH-Px and SOD in treatment Ⅰ and Ⅱ were lower than that of basic control(P>0.05),and the lever of MDA in treatment Ⅰ and Ⅱ were higher than that of basic control(P>0.05) in the47th testing day. The level of Glu and LDH in treatment Ⅰ and Ⅱ were lower than that of basic control (P>0.05) in the21st testing day.The level of CPK and ALP in treatment Ⅰ were lower than that of basic control(P>0.05), and the level of CPK and ALP in treatment Ⅱ were higher than that of basic control(P>0.05) in the47th testing day.The level of TP of treatment Ⅱ were lower than that of basic control(P<0.05) and lower than that of treatment Ⅱ (P>0.05) in the21st testing day.The levels of TP of treatment Ⅰ and Ⅱ were lower than that of basic control(P>0.05) in the47th testing day.The level of BUN of treatment Ⅰ was higher than that of basic control(P>0.05),and that of treatment Ⅱ was lower than that of basic control(P>0.05) in the21st and47th testing day.It is showed that10g/d rumen protected betaine had a good effect on blood index of heat stress in dairy cows.Experiment three:The design of experiment was the same as experiment one and the collection of blood samples was the same as experiment two.And the Hsp70mRNA level was analyzed in blood.The result showed that the Hsp70mRNA level were lower in basic control,treatment Ⅰ and Ⅱ in the21st and47th testing day than that before test days.The Hsp70mRNA level in basic control was lower than that in treatment Ⅰ and Ⅱ in the47th testing day,but it is not significant difference(P>0.05).