石河子市规模牛场三个品系牛BVD-MD血清学监测

BVD-MD Serological Monitoring of Three Strains of Cattle in Large-scale Cattle Farms in Shihezi City

针对石河子市部分规模牛场临床出现的早产、流产、弱胎、犊牛腹泻等症状,进行了牛病毒性腹泻/黏膜病(BVD-MD)血清学调查,旨在掌握该病感染状况和品系间牛发生犊牛腹泻和成母牛早产等疾病之间差异,为防控净化BVD-MD提供参考。选择石河子市范围内3个未免疫BVD-MD疫苗牛场,分别饲养中国荷斯坦牛(以下简称荷牛),弗莱维赫乳肉兼用牛×荷斯坦牛杂交代乳肉兼用牛(以下简称弗荷牛),挪威红牛×荷斯坦牛杂交代乳肉兼用牛(以下简称挪荷牛);共计采集血清样品2 981份,分别使用牛病毒性腹泻(BVD)实时荧光RT-PCR监测和牛病毒性腹泻ELISA方法监测抗原和抗体。并通过临床观察记录三个品系牛发病情况,分析品系间发病的差异。实时荧光RT-PCR监测抗原阳性总检出率为1.85%(55/2981),荷牛阳性检出率为2.17%,弗荷牛阳性检出率为1.35%,挪荷牛阳性检出率为2.05%;品系之间抗原阳性率差异不显著(P>0.05);三个品系的犊牛、青年牛、后备牛、成母牛均监测到BVDV,说明BVDV感染不因品系不同而存在差异,不同品系牛之间不影响BVDV的流行。牛病毒性腹泻ELISA方法监测阳性总检出率为28.75%,荷牛阳性检出率为32.85%,弗荷牛阳性检出率为28.06%,挪荷牛阳性检出率为25.41%;三个品系牛之间抗体阳性率差异不显著(P>0.05)。分析三个品系牛临床发病(犊牛腹泻与成母牛早产、流产、弱胎等)数据显示:弗荷犊牛与挪荷犊牛腹泻发病率较荷犊牛发病率差异极显著(P<0.01);弗荷成母牛与挪荷成母牛发生早产、流产、弱胎等发病率较荷成母牛发病率差异显著(P<0.05)。调查显示:一是石河子市规模牛场三个品系牛均存在BVDV感染,且品系间感染率差异不显著(P>0.05);二是弗荷牛和挪荷牛较荷牛有更强的抵抗疾病的能力。监测结果为石河子市规模牛场BVD-MD的防控和净化工作提供了技术支撑。

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 milkmeat dual-purpose cattle(hereinafter referred to as Fhort cattle),Norwegian Red cattle×Holstein cows hybrid milkmeat 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.