Type

Journal Article

Authors

D P Berry
S Brotherstone
I M Higgins
A.R. Cromie
M Good
S J More
M L Bermingham

Subjects

Biochemistry

Topics
female cattle linear models breeding genetics tuberculosis bovine animals phenotype male genetic predisposition to disease physiology ireland dairying

Genetics of tuberculosis in Irish Holstein-Friesian dairy herds. (2009)

Abstract Information is lacking on genetic parameters for tuberculosis (TB) susceptibility in dairy cattle. Mycobacterium bovis is the principal agent of tuberculosis in cattle. The objective of this study was to quantify the genetic variation present among Irish Holstein-Friesian dairy herds in their susceptibility to M. bovis infection. A total of 15,182 cow and 8,104 heifer single intradermal comparative tuberculin test (SICTT, a test for M. bovis exposure and presumed infection) records from November 1, 2002, to October 31, 2005, were available for inclusion in the analysis. Data on observed carcass TB lesions from abattoirs were also available for inclusion in the analysis. The only animals retained were those present in a herd during episodes in which at least 2 animals showed evidence of infection; this ensured a high likelihood of exposure to M. bovis. Linear animal models, and sire and animal threshold models were used to estimate the variance components for susceptibility to M. bovis-purified protein derivative (PPD) responsiveness and confirmed M. bovis infection. The heritability estimates from the threshold sire models were biased upward because the relatedness between dam-daughter pairs was ignored. The threshold animal model produced heritability estimates of 0.14 in cows and 0.12 in heifers for susceptibility to M. bovis-PPD responsiveness, and 0.18 in cows for confirmed M. bovis infection susceptibility. Therefore, exploitable genetic variation exists among Irish dairy cows for susceptibility to M. bovis infection. Sire rankings from the linear and threshold animal models were similar, indicating that either model could be used for the analysis of susceptibility to M. bovis-PPD responsiveness. A favorable genetic correlation close to unity was observed between susceptibility to confirmed M. bovis infection and M. bovis-PPD responsiveness, indicating that direct selection for resistance to M. bovis-PPD responsiveness will indirectly reduce susceptibility to confirmed M. bovis infection. Data from the national TB eradication program could be used routinely to estimate breeding values for susceptibility to M. bovis infection.
Collections Ireland -> Teagasc -> PubMed

Full list of authors on original publication

D P Berry, S Brotherstone, I M Higgins, A.R. Cromie, M Good, S J More, M L Bermingham

Experts in our system

1
D P Berry
Teagasc
Total Publications: 215
 
2
Isabella M. Higgins
Teagasc
Total Publications: 13
 
3
A.R. Cromie
Teagasc
Total Publications: 27
 
4
M Good
University College Dublin
Total Publications: 28
 
5
S J More
University College Dublin
Total Publications: 171