A SEARCH FOR ASSOCIATIONS BETWEEN MAJOR HISTOCOMPATIBILITY COMPLEX RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISM BANDS AND RESISTANCE TO HAEMONCHUS-CONTORTUS INFECTION IN SHEEP

Polymorphic bands were detected within the DQB and DRB regions of the ovine major histocompatibility complex by probing TaqI digested DNA fr om three large sheep half-sib families derived from a highly resistant ram. All animals were phenotypically assessed for Haemonchus contortu s resistance by faecal egg counts and associations with RFLP bands and haplotypes were estimated using mixed model, best linear unbiased pre diction statistical methods. Although the highly resistant sire was ho mozygous at the MHC, no significant associations were found between an y band or haplotype and faecal egg count.