title: Evidence for genetic variance in resistance to tuberculosis in Great Britain and Irish Holstein-Friesian populations.
abstract: BACKGROUND
  Here, we jointly summarise scientific evidence for genetic variation in resistance to infection with Mycobacterium bovis, the primary agent of bovine tuberculosis (TB), provided by two recent and separate studies of Holstein-Friesian dairy cow populations in Great Britain (GB) and Ireland.
  
  
  METHODS
  The studies quantified genetic variation within archived data from field and abattoir surveillance control programmes within each country. These data included results from the single intradermal comparative tuberculin test (SICTT), abattoir inspection for TB lesions and laboratory confirmation of disease status. Threshold animal models were used to estimate variance components for responsiveness to the SICTT and abattoir confirmed M. bovis infection. The link functions between the observed 0/1 scale and the liability scale were the complementary log-log in the GB, and logit link function in the Irish population.
  
  
  CONCLUSIONS
  The estimated heritability of susceptibility to TB, as judged by responsiveness to the SICTT, was 0.16 (0.012) and 0.14 (0.025) in the GB and Irish populations, respectively. For abattoir or laboratory confirmation of infection, estimates were 0.18 (0.044) and 0.18 (0.041) from the GB and the Irish populations, respectively.
  
  
  CONCLUSIONS
  Estimates were all significantly different from zero and indicate that exploitable variation exists among GB and Irish Holstein Friesian dairy cows for resistance to TB. Epidemiological analysis suggests that factors such as variation in exposure or imperfect sensitivity and specificity would have resulted in underestimation of the true values.
authors.affiliation: The Roslin Institute, Roslin Biocentre, Roslin, Midlothian EH25 9RG, UK.
authors.forename: Mairead L
authors.initials: ML
authors.lastname: Bermingham
authors.affiliation: Institute of Evolutionary Biology, University of Edinburgh, West Mains Road, Edinburgh EH9 3JT, UK.
authors.forename: Susan
authors.initials: S
authors.lastname: Brotherstone
authors.affiliation: Moorepark Production Research Centre, Fermoy, Co. Cork, Ireland.
authors.forename: Donagh P
authors.initials: DP
authors.lastname: Berry
authors.affiliation: Centre for Veterinary Epidemiology and Risk Analysis, UCD School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Simon J
authors.initials: SJ
authors.lastname: More
authors.affiliation: Department of Agriculture, Fisheries and Food, Kildare St., Dublin 2, Ireland.
authors.forename: Margaret
authors.initials: M
authors.lastname: Good
authors.affiliation: The Irish Cattle Breeding Federation, Bandon, Co. Cork, Ireland.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Cromie
authors.affiliation: Institute of Evolutionary Biology, University of Edinburgh, West Mains Road, Edinburgh EH9 3JT, UK.
authors.forename: Ian Ms
authors.initials: IM
authors.lastname: White
authors.affiliation: Centre for Veterinary Epidemiology and Risk Analysis, UCD School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Isabella M
authors.initials: IM
authors.lastname: Higgins
authors.affiliation: Scottish Agricultural College, Bush Estate, Penicuik, Midlothian EH26 0PH, UK.
authors.forename: Mike
authors.initials: M
authors.lastname: Coffey
authors.affiliation: Veterinary Laboratories Agency-Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK.
authors.forename: Sara H
authors.initials: SH
authors.lastname: Downs
authors.affiliation: The Roslin Institute, Roslin Biocentre, Roslin, Midlothian EH25 9RG, UK.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Glass
authors.affiliation: The Roslin Institute, Roslin Biocentre, Roslin, Midlothian EH25 9RG, UK.
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Bishop
authors.affiliation: Veterinary Laboratories Agency-Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK.
authors.forename: Andy P
authors.initials: AP
authors.lastname: Mitchell
authors.affiliation: Veterinary Laboratories Agency-Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK.
authors.forename: Richard S
authors.initials: RS
authors.lastname: Clifton-Hadley
authors.affiliation: The Roslin Institute, Roslin Biocentre, Roslin, Midlothian EH25 9RG, UK.
authors.forename: John A
authors.initials: JA
authors.lastname: Woolliams