This article is part of the supplement: Proceedings of the International Symposium on Animal Genomics for Animal Health (AGAH 2010)
Evidence for genetic variance in resistance to tuberculosis in Great Britain and Irish Holstein-Friesian populations
- Equal contributors
1 The Roslin Institute, Roslin Biocentre, Roslin, Midlothian EH25 9RG, UK
2 Institute of Evolutionary Biology, University of Edinburgh, West Mains Road, Edinburgh EH9 3JT, UK
3 Moorepark Production Research Centre, Fermoy, Co. Cork, Ireland
4 Centre for Veterinary Epidemiology and Risk Analysis, UCD School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland
5 Department of Agriculture, Fisheries and Food, Kildare St., Dublin 2, Ireland
6 The Irish Cattle Breeding Federation, Bandon, Co. Cork, Ireland
7 Scottish Agricultural College, Bush Estate, Penicuik, Midlothian EH26 0PH, UK
8 Veterinary Laboratories Agency-Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
BMC Proceedings 2011, 5(Suppl 4):S15 doi:10.1186/1753-6561-5-S4-S15Published: 3 June 2011
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.
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.
Results and discussion
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.
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.