Epidemiological Investigation Of BVD,IBR,BPI And Brucellosis In Part Of Scale Dairy Farms Of The Northern Xinjiang

Cows reproductive disorders refers to the reproductive ability decline caused by a variety of factors when the cow reach normal sexual maturation age.Clinical manifestations include infertility, miscarriage, stillbirth, postpartum endometritis,etc. The reasons of cow reproductive disorders are non-infectious factors and infectious factors. Non-infectious factors include poor feeding and management, poor cow’s health, improper reproductive technologies,etc. Infectious factors caused by infectious diseases. Among them, bovine viral diarrhea virus(BVDV), infectious bovine rhinotracheitis virus(IBRV), bovine parainfluenza virus type 3(BPIV-3) and Brucella are the important pathogen. Cows reproductive disorders causes great economic losses, serious influence and restricts the sustainable and healthy development of milk cow industry.But the infectious factors of cows reproductive disorders were unclear in the Xinjiang region. Therefore, studies on field, serum and molecular epidemiological investigations of cows reproductive disorders will provide important guiding role to draw up scientific and effective prevention and control measures.To investigate the prevalence of BVD, IBR, BPI and brucellosis. Four large-scale dairy farms located in the northern Xinjiang were chosen. Field, serum and molecular epidemiological investigation were carried out. The results of the study were as follows:1. Field epidemiological surveyOccurrence features of cow abortion in large-scale dairy farms from 2011-2013 were found out. The abortion rate was 9.95%(361/3629) during 2011 ~ 2013. Abortion was associated with parity, pregnancy days and season.①The relationship between abortion and parity was that abortion occurred mainly in the first 1-3 parities, abortion occurred seriously in the first pregnancy and less after 4 parities.②The relationship between abortion and pregnancy days,abortion occurred during each period of pregnancy, but occurred mainly between 60 ~ 120 d of pregnancy.③The relationship between abortion and season, abortion reach peak in spring and summer(March to August),especially in summer(June to August),and abortion rarely occurs in the autumn(September to November).2. Serum epidemiological investigationThe average antibody of anti-BVDV/IBRV/BPIV-3 positive rate were 75.4%、87.4% and91.4% in four large-scale dairy farms of the northern Xinjiang. The antibody of anti-BVDV/IBRV/BPIV-3 were detected from serum of the abortion and stillbirth cows,metritis cows, 1 to 2 months’ calves with pneumonia and calves without feeding colostrum.The average anti-brucella antibody positive rate was 25.1% in serum of the abortion and stillbirth cows.3. Molecular epidemiological investigationTissues of abortion and stillbirth fetuses, nasal swabs of 1 to 2 months calves with pneumonia disease were detected for BVDV, IBRV and BPIV-3 specific gene by fluorescent probe RT-PCR/PCR method. The BVDV, IBRV and BPIV-3 detection rate were 11.29%(28/248), 9.26%(15/162) and 10.00%(18/180) respectively. In 59 tissues of abortion and stillbirth fetuses, BVDV, IBRV and BPIV-3 detection rate were(15/59), 5.08%(3/59) and25.42%(15/59) respectively, while above pathogens were negative in bull semen.4. Mixed infectionsThe results of serum epidemiological investigation and molecular epidemiological investigation also showed 2 ~ 3 kinds virus genes were co-existion in the nasal swabs of calf with pneumonia and tissues of abortion and stillbirth fetuses. 2 ~ 4 kinds viral antibody were co-exist in the serum of calf and abortion and stillbirth adult cows. The antibody of anti-BVDV/IBRV/BPIV-3/Brucella co-existion rate was 22.6% in the serum of abortion and stillbirth adult cows.The results suggested that mix infection phenomenon of BVDV, IBRV,BPIV-3 and Brucella was relatively common in cows reproductive disorders.In this study, infection and prevalence of BVD, IBR, BPI and brucellosis in cows reproductive disorders were clarified preliminarily in scale dairy farms of the northern Xinjiang. These epidemiological data will play an important role to make the preventive and control strategies and measures for cows reproductive disorders.