Evaluation Of BVD-MD Diagnosis And BVD-MD/IBR Combined Vaccine In A Cattle Farm

OBJECTIVE: Study the reason of death of pregnant cow and calves in certain large-scale cattle farm in Xinjiang and deter mine the immune effect of BVD-MD/IBR bige miny inactivated vaccine which is on sale in market.And provide reference for the following promotion of BVD-MD/IBR bige miny inactivated vaccine.Methods:1.The epidemiological investigation,clinical exa mination,pathologic exa mination,bacteriological examination and RT-PCR were performed.The PCR products were analyzed by sequence analysis.2.Thirty-eight pregnant cow in the milk dry period is collected from this large-scale cattle.They are divided into two groups.Develop an immunization program,one group is injected the BVD-MD/IBR big eminy inactivated vaccine,the other group is injected hog cholera vaccine.These two groups are collected the serum separated from blood from caudal vein respectively after 7 and 14 days after the first immune and 7 days after the second immune.Collect the colostrum of cow after 7 days of cattle birth and exam the BVDV antibody level of serum and colostrum by directly using the ELISA method.And compare the changes of BVDV antibody level before and after inoculating the BVD-MD/IBR big eminy inactivated vaccine;antibody level of hog cholera virus in the serum and colostrum is examined by the blocking ELISA method after inoculating the hog cholera vaccine.3.The BVDV antibody level of serum is examined by indirectly using the ELISA method when 7 days after the birth of calves after inoculating these two kinds of vaccines.Adopt the double-antibody sandwich ELISA method to examine the BVDV antigen of calves in its blood and excrement after the cow is inoculated with these two kings of vaccine and accesses the healthy condition of calves when it is 3 months old.Results: 1.The field investigation show that there is sixty-seven cows attacked by disaster from March to May among which the adult pregnant cows were forty-one,eight cows is died and the case fatality rate is 19.51%;twenty-six calves after birth of 2-8 weeks are attacked with disaster,six cows are died.The case fatality rate is 23.07%.The adult cows and calves all presented the fevescence,dental ulcer and diarrhea.Four pregnant cows happened abortion,dead fetus and claudication;clinical manifestations get from dissection,anabrosis of mucosa,ecclasis and bleeding,are the typical characteristics of BVD.Examine no germ is observed after collecting the heart blood and hepatic tissue of died cows under the sterility after inoculating it in LB meat soup for 12 hours;The aimed strip of 286 bp has been got by detecting the seawand swab and intestinal content swab of three dead cows adopted the method of BVDV specific primers.And the homology with the BVDV referenced plant in Genbank is 94.2%~98.5%.2.The BVDV antibody in serum and colostrum is detected by the BVDV indirect ELISA method.The result show that there are 4 cows with positive antibody before the immune,the positive rate is 21.05%;twelve cows appear positive BVDV antibody,the positive rate is 63.16%;nineteen cows appeared positive BVDV antibody after the second immune,the positive rate is 100%.The HCV antibody in serum and colostrum is detected by the hog cholera blocking ELISA method.The result shows that antibody positive rate of the second immune is 94.7% and that of colostrum is 100%.3.Nineteen calves appeared positive BVDV antibody,positive rate is 100%;the BVDV antigen was detected by BVDV double sandwich ELISA.The HCV antibody positive rate of calves is 84.21%.There is no difference with the calves born by the cows injected BVD-MD/IBR bigeminy inactivated vaccine in healthy situation.The results showed that the positive rate of BVDV antigen in calf serum and feces was 0,and the unvaccinated cows were not found in cows with BVD/IBR inactivated vaccine and swine fever vaccine.The positive rate of antigen was 21.05%.BVDV detecting by BVDV double-antibody ELISA was all positive;observe the spirit and appetite three months after birth of calves,there is no BVDV symptom within one month.Conclusion: 1.The death of cows and calves is mainly caused by the BVDV infection in this large-scale cattle farm.2.It verifies that BVD-MD/IBR bige miny inactivated vaccine has the excellent immune effect.3.It verifies that hog cholera vaccine has the immune effect on prevention of BVDV infection.