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Variance Components and Genome Wide Association Analysis of Mycobacterium bovis Infection in Dairy and Beef Cattle
Infection of livestock with bovine tuberculosis (bTB; M. bovis) is of major economical concern in many countries; approximately 15,000 to 20,000 cattle are infected per annum in Ireland. The objective of this study was to quantify the genetic variation for bTB susceptibility in Irish dairy and beef cows. A total of 105,914 cow, 56,904 heifer and 21,872 steer single intra-dermal comparative tuberculin test records were available. Variance components for bTB were estimated using animal linear mixed models and co-variances were estimated using sire linear mixed models. The heritability for susceptibility to bTB ranged from 0.08 (heifers in dairy herds) to 0.19 (heifers in beef herds).
Using 842 high density bull genotypes (n=630,352) and deregressed estimated breeding values for bTB susceptibility a genome wide association scan for bTB susceptibility was performed using a single SNP regression approach.
Keywords:
Genetics
Dairy cattle
Tuberculosis
GWAS
