 Growth characteristics, acid-fastness and 16S rRNA gene sequencing results were consistent with those of the genus "Mycobacterium".Biochemical reactions, growth characteristics and mycolic acid profiles (HPLC) resembled those of "Mycobacterium shottsii", a non-pigmented mycobacterium also isolated during the same epizootic.Sequencing of the 16S rRNA genes, the gene encoding the exported repeated protein ("erp") and the gene encoding the 65 kDa heat-shock protein ("hsp"65) and restriction enzyme analysis of the "hsp"65 gene demonstrated that this group of isolates is unique.