Abstract
Based on 2 previous surveys on the occurrence of infection with bovine virus diarrhoea virus (BVDV) in Danish and Michigan dairy herds, the prevalence and incidence of the infection were compared. The presence of certain possible risk factors for the occurrence of infection in the 2 areas were summarized and it was investigated if any of these risk factors had significant effect on the presence of animals persistently infected (PI) with BVDV in the dairy herds. Information on the cattle population density in the 2 areas was obtained from statistical yearbooks. Further information for the individual farms on age distribution, housing of animals, herd size, pasturing and purchasing policy was gathered. The prevalence of PI animals was more than 10 times higher in Denmark as compared to Michigan. In herds without PI animals, the annual incidence of seroconversion as calculated from the age specific prevalence of antibody carriers varied in most age groups between 20–25% in Denmark and between 5–10% in Michigan. All investigated risk factors except for herd size were in favour of a lower prevalence of infection in Michigan. The use of having animals on pasture and at the same time having purchased more than 40 animals within recent 31/2–4 years were significantly associated with presence of PI animals in the dairy herds (p = 0.01) when tested by the Mantel-Haenszel χ2. Using mul-tivariable logistic regression, the occurrence of PI animals was found to be significantly related to the study area (Michigan and Denmark) as well as to herd size and purchase intensity.
Keywords: pestivirus, cattle, epidemiology, Denmark, USA
Sammendrag
Baseret på to tidligere undersøgelser over forekomsten af infektion med bovin virusdiarré virus (BVDV) i malkekvægsbesætninger i Danmark og Michigan blev der foretaget en sammenligning af prævalensen og incidensen af infektionen mellem de to områder. Tilstedeværelsen af mulige risikofaktorer for forekomst af infektion blev opsummeret, og det blev undersøgt, hvorvidt nogle af disse risikofaktorer havde signifikant indflydelse på forekomst af persistent inficerede (PI) dyr i besætningerne.
Data vedrørende popuiationstætheden af kvæg i de to områder blev indsamlet fra statistiske årbøger Herudover blev der fra hver enkel besætning indsamlet oplysninger om aldersfordeling, opstaldning af dyr, besætningsstørrelsc, brug af sommergræsning samt indkøb af dyr.
Prævalensen af PI-dyr var mere end 10 gange højere i Danmark sammenlignet med Michigan, I besætninger uden PI-dyr blev den årlige incidens af serokonverteringer beregnet ud fra den aldersspecifikke prævalens af antistofpositive dyr. Incidensen varierede i de fleste aldersgrupper mellem 20–25% i Danmark sammenlignet med 5–10% i Michigan.
Alle undersøgte risikofaktorer undtagen besætningsstarrelse ville befordre en lavere prævalens af infektionen i Michigan. Ved anvendelse af MantclHaenszel χ2 vistes brug a f sommergræsning samtidig med, at der var indkøbt over 40 dyr indenfor de seneste 31/2-4 år, at have signifikant effekt på forekomst af Pl-dyr i besætningerne (p = 0.01). Ved anvendelse af multipel logistisk regression fandtes forekomsten af PI-dyr at være signifikant relateret til undersøgelsesområde (Michigan og Danmark), bcsætningsstørrelse og indkøbsintensitet.
Full Text
The Full Text of this article is available as a PDF (2.5 MB).
References
- Agricultural Statistics 1990, Danmarks Statistik, Copenhagen, 256 pp.
- Alenius S, Jacobsen S-O, Cafaro E: Frequency of bovine viral diarrhea virus infections in Sweden among heifers selected for artificial insemination. Proc. World Congr. Diseases of Cattle. 1986, 14, 204–207.
- Bolin SR, McClurkin AW, Coria MF. Frequency of persistent bovine viral diarrhea virus infection in selected cattle herds. Amer. J. vet. Res. 1985;46:2385–2387. [PubMed] [Google Scholar]
- Brock KV, Radwan GS: Detection of bovine viral diarrhea virus in bulk milk samples by PCR amplification. In: Edwards S (ed): Proceedings of the Second Symposium on pestiviruses 1-3 October 1992. 1993, 223–226.
- Brownlie J, Clarke MC, Howard CJ, Pocock DH. Pathogenesis and epidemiology of bovine virus diarrhoea virus infection of cattle. Annls. Rech. vét. 1987;18:157–166. [PubMed] [Google Scholar]
- County Food and Agricultural Development Statistics, 1992, Michigan Department of Agriculture, Lansing, Michigan.
- Danish Statistical Yearbook, 1991, Danmarks Stati-stik Copenhagen, 575 pp.
- Edwards S, Drew T. Prevalence of bovine virus diarrhoea virus viraemia. Vet. Ree. 1987;120:71. doi: 10.1136/vr.120.3.71. [DOI] [PubMed] [Google Scholar]
- Houe H. Serological analysis of a small herd sample to predict presence or absence of animals persistently infected with bovine viral diarrhoea virus (BVDV) in dairy herds. Res. Vet. Sci. 1992;53:320–323. doi: 10.1016/0034-5288(92)90133-M. [DOI] [PubMed] [Google Scholar]
- Houe H. Bovine virus diarrhoea virus: detection of Danish dairy herds with persistently infected animals by means of a screening test of ten young stock. Prev. Vet. Med. 1994;19:241–248. doi: 10.1016/0167-5877(94)90092-2. [DOI] [Google Scholar]
- Houe H, Baker JC, Maes RK, Ruegg PL, Lloyd JW. Application of antibody titers against bovine viral diarrhea virus (BVDV) as a measure to detect herds with presence of cattle persistently infected with BVDV J. Vet. Diag. Invest. 1995;7:327–332. doi: 10.1177/104063879500700305. [DOI] [PubMed] [Google Scholar]
- Houe H, Baker JC, Maes RK, Wuryastuti H, Wasito R, Ruegg PL, Lloyd JW. Prevalence of cattle persistently infected with bovine viral diarrhea virus in 20 dairy herds in two counties in central Michigan and comparison of prevalence of antibody positive cattle among herds with different infection and vaccination status. J. Vet. Diag. Invest. 1995;7:321–326. doi: 10.1177/104063879500700304. [DOI] [PubMed] [Google Scholar]
- Houe H, MeylingA Prevalence of bovine virus diarrhoea (BVD) in 19 Danish dairy herds and estimation of incidence of infection in early pregnancy. Prev. Vet. Med. 1991;77:9–16. doi: 10.1016/S0167-5877(05)80040-6. [DOI] [Google Scholar]
- Houe H, Palfì V. Estimation of herd incidence of infection with bovine virus diarrhoea virus (BVDV) in herds previously without animals persistently infected with BVDV. Acta vet. scand. 1993;34:133–137. doi: 10.1186/BF03548201. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Howard CJ, Brownlie J, Thomas LH. Prevalence of bovine virus diarrhoea virus viraemia in cattle in the UK. Vet. Ree. 1986;779:628–629. [PubMed] [Google Scholar]
- Lilienfeld AM, Lilienfeld DE. Foundations of epidemiology. New York: Oxford University Press; 1980. p. 375. [Google Scholar]
- McClurkin AW, Littledike ET, Cutlip RC, Frank GH, Coria MF, Bolin SR. Production of cattle immu-notolerant to bovine viral diarrhea virus. Can. J. Comp. Med. 1984;4:156–161. [PMC free article] [PubMed] [Google Scholar]
- Meyling A. Detection of BVD virus in viremic cattle by an indirect immunoperoxidase technique. In: McNulty MS, MacFerrari JB, editors. Recent advances in virus diagnosis. Boston: Martinus Nijhoff Publishers; 1984. pp. 37–46. [Google Scholar]
- Meyling A, Houe H, Jensen AM. Epidemiology of bovine virus diarrhoea virus. Rev. sci. tech. Off. int. Epiz. 1990;9:75–93. doi: 10.20506/rst.9.1.489. [DOI] [PubMed] [Google Scholar]
- Michigan Agricultural Statistics, 1993, Michigan Department of Agriculture, Lansing, Michigan, 89 pp.
- RoederPL, HarknessJW BVD virus infection: Prospects for control. Vet. Ree. 1986;118:143–147. doi: 10.1136/vr.119.6.143. [DOI] [PubMed] [Google Scholar]
- SAS Institute Inc. SAS STAT™ Users Guide. Cary, NC: SAS Institute Inc.; 1988. p. 1928. [Google Scholar]
- Shimizu M, Satou K. Frequency of persistent infection of cattle with bovine viral diarrhea-mucosal disease virus in epidemic areas. Jpn. J. Vet. Sci. 1987;49:1045–1051. doi: 10.1292/jvms1939.49.1045. [DOI] [PubMed] [Google Scholar]
- Yamini B, Mullaney TP, Trapp AL: Causes of abortion in bovine: 1208 cases (1983-1994). J. Vet. Diag. Invest. (Submitted for publication).
