Author:

Abstract:

The Belgian Blue cattle breed is extremely sensitive to psoroptic mange, a severe dermatitis caused by the mite Psoroptes ovis. This marked breed predisposition indicates that the susceptibility to psoroptic mange is partly heritable, opening perspectives for a genome wide association study (GWAS). Determination of the genetic factors underlying this high sensitivity of the Belgian Blue breed requires the definition of a clear phenotype. This mange phenotype was defined based on lesion extent, lesion appearance and mite counts, measured at three consecutive farm visits. In this study, a GWAS was performed using the Illumina Bovine SNP50 v2 BeadChip to identify locations linked to mange sensitivity in 496 Belgian Blue animals sampled at 18 different farms. The Glascow program was used to allow the implementation of a linear mixed model on haplotypes inferred from the genomic data. Considering mange sensitivity as a quantitative phenotype, 110 extreme cases (sensitive/resistant) were selected. A GWAS on these extreme phenotypes showed a promising signal at the telomere of chromosome 11. This genome scan is the first attempt to unravel the genetics of psoroptic mange sensitivity, promising economic as well as welfare advantages.