Association between alleles of the ovine major histocompatibility complex and resistance to footrot.

Variation in natural resistance to footrot may be genetically derived, implying that genetic markers for resistance may exist and allow selection of superior animals. In this study association between variation within the ovine MHC class II region and resistance to footrot was investigated in two trials. Half-sib progeny were subjected to a field challenge with footrot and their condition subsequently recorded. The animals were then typed at their MHC class II loci to investigate associations between inherited paternal haplotype and footrot status. In the first trial an association between MHC haplotype and footrot status was observed across all animals (P = 0.005), when the self-curing and resistant animals were combined (P = 0.002) and when the self-curing animals were excluded from the analysis (P = 0.001). No association was observed in the second trial, a result attributed to the dry weather conditions which led to poor disease transmission and unreliable disease classification.