BVD-MD Serological Monitoring of Three Strains of Cattle in Large-scale Cattle Farms in Shihezi City
In view of the clinical symptoms of premature delivery,abortion,weak fetus,calf diarrhea and other symptoms in some large-scale cattle farms in Shihezi city,the purpose of this study is to grasp the infection status of bovine viral diarrhea/mucosal disease(BVD-MD)and the differences between calf diarrhea and premature delivery of adult cows among strains,so as to provide reference for the prevention and control of BVD-MD,three non-immunized BVD-MD vaccine cattle farms in Shihezi city were selected and fed with Chinese Holstein cows(hereinafter referred to as Holstein cows),Fleckvieh milk-meat dual-purpose cattle×Holstein cows hybrid milk-meat dual-purpose cattle(hereinafter referred to as Fhort cattle),Norwegian Red cattle×Holstein cows hybrid milk-meat dual-purpose cattle(hereinafter referred to as Norhe cattle).A total of 2981 serum samples were collected,and antigen and antibody were monitored by bovine viral diarrhea(BVD)real-time fluorescence RT-PCR and bovine viral diarrhea ELISA,respectively.The incidence of the three strains of cattle was recorded through clinical observation,and the difference in disease resistance between the strains was analyzed.The total positive detection rate of real-time fluorescence RT-PCR was 1.85%(55/2981),the positive detection rate of Holtein cattle was 2.17%,the positive detection rate of Fhort cattle was 1.35%,and the positive detection rate of Norhe cattle was 2.05%.There was no significant difference in antigen positive rate between strains(P>0.05).BVDV was detected in calves,young cattle,reserve cattle and adult cows of the three strains,indicating that BVDV infection was not different due to different strains,and different strains of cattle did not affect the prevalence of BVDV.The total positive detection rate of bovine viral diarrhea by ELISA was 28.75%,the positive detection rate of Holstein cattle was 32.85%,the positive detection rate of Fhort cattle was 28.06%,and the positive detection rate of Norhe cattle was 25.41%.There was no significant difference in antibody positive rate among the three strains of cattle(P>0.05).The analysis of the clinical incidence of three strains of cattle(calf diarrhea and premature birth,abortion,weak fetus,etc.)showed that the incidence of diarrhea in Fhort calves and Norhe calves was significantly different from that in Holstein calves(P<0.01).The incidence of premature delivery,abortion and weak fetus in Fhort adult cows and Norhe adult cows was significantly different from that in Holstein adult cows(P<0.05).It is confirmed that:First,BVDV infection exists in all three strains of cattle in large-scale cattle farms in Shihezi city,and there is no significant difference in infection rate between strains(P>0.05).Second,Fhort cattle and Norhe cattle have stronger ability to resist diseases than Holstein cattle.The monitoring results provided technical support for the prevention,control and purification of BVD-MD in large-scale cattle farms in Shihezi city.
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