Footrot is the most costly and impacting animal welfare disease in small ruminants. The putative gene group with variation from highly resistance to highly susceptible allele has been identified and a DNA marker (DQA2) is being developed for marker assisted selection in sheep. Katahdin and Katahdin crossbred sheep were screened for footrot resistant gene markers. A value for a pair of alleles was derived and animals were classed into
five categorical groups (1, 2, 3, 4, and 5) from highest to lowest resistance to footrot. White blood cell types were analyzed in the progeny groups. Both allelic and genotypic distributions were significantly (P < 0.01) different in the
five gene marker score groups. There was no difference (P > 0.05) in white blood cell types by marker score groups, but a significant difference for hematocrits (P < 0.05) between breeds
