Research article - Peer-reviewed, 2015
Bovine respiratory syncytial virus and bovine coronavirus in Swedish organic and conventional dairy herds
Wolff, Cecilia; Emanuelson, Ulf; Ohlson, Anna; Alenius, Stefan; Fall, NilsAbstract
Background: Infections with bovine respiratory syncytial virus (BRSV) and bovine coronavirus (BoCV) are endemic to the cattle populations in most countries, causing respiratory and/or enteric disease. It has been demonstrated that herds can remain free from these infections for several years also in high prevalence areas. Organically managed (OM) dairy herds have been shown to have lower seroprevalence of both viruses compared to conventionally managed (CM) herds. The objective of this study was to challenge the hypothesis of a lower occurrence of BRSV and BoCV in OM compared to CM dairy herds. In November 2011, May 2012 and May 2013 milk samples from four homebred primiparous cows were collected in 75 to 65 OM and 69 to 62 CM herds. The antibody status regarding BRSV and BoCV was analysed with commercial indirect ELISAs. Herds were classified as positive if at least one individual sample was positive.Results: The prevalence of positive herds ranged from 73.4% to 82.3% for BRSV and from 76.8% to 85.3% for BoCV among OM and CM herds, over the three sampling occasions. There was no statistically significant difference between OM and CM herds at any sampling occasion. The incidence risk of newly infected herds did not differ statistically between OM and CM herds at any sampling occasion, neither for BRSV nor for BoCV. The incidence of herds turning sero-negative between samplings corresponded to the incidence of newly infected. Bulk tank milk (BTM) samples were also sampled in the herds and analysed. Several herds were negative on individual samples but positive in BTM. Herd-level data on production, health and reproduction were retrieved from VAXA Sweden and the study herds were representative of the source population.Conclusion: There was no difference in prevalence of or incidence risk for BRSV or BoCV between Swedish OM and CM herds. Because the incidence of herds becoming seropositive was balanced by herds becoming seronegative it should be possible to lower the prevalence of these two infections among Swedish dairy cattle herds if biosecurity is improved.Keywords
Bovine respiratory disease; Diarrhoea; Cattle; Disease prevalence; Disease incidence; ELISAPublished in
Acta Veterinaria Scandinavica2015, volume: 57, article number: 2
Publisher: BIOMED CENTRAL LTD
Authors' information
Wolff, Cecilia
Swedish University of Agricultural Sciences, Department of Clinical Sciences
Swedish University of Agricultural Sciences, Department of Clinical Sciences
Ohlson, Anna
Växa Sverige
Swedish University of Agricultural Sciences, Department of Clinical Sciences
Swedish University of Agricultural Sciences, Department of Clinical Sciences
UKÄ Subject classification
Clinical Science
Publication Identifiers
DOI: https://doi.org/10.1186/s13028-014-0091-x
URI (permanent link to this page)
https://res.slu.se/id/publ/64747