Validating Candidate Alleles
Table 4 shows that candidate alleles were only partially observed in the tested population. The most frequent alleles in the susceptible and resistant groups were DRB3*52 and *51, respectively. This result shows that DRB3*52 and *1, which were candidates for susceptible alleles, were found only in the susceptible group, and DRB*51, *15, and *22, which were candidates for resistant alleles, were found only in the resistant group. This result confirmed that DRB3*52 can be considered the most susceptible allele and DRB3*51 the most resistant allele in Holstein × Zebu cattle raised under tropical conditions. However, DRB3*16, *8, and *23 cannot be confirmed with certainty as either susceptible or resistant alleles, because they were found in both groups.