Inheritance of spinal dysmyelination in calves

A study was performed to establish the inheritance of spinal dysmyelination in cross-bred American Brown Swiss calves. Daughters of a carrier bull were mated to another carrier resulting in 254 calves. 228 calves were found to be normal while 25 calves were affected with spinal dysmyelination. One calf was excluded from the study. The number of affected males and females did not differ significantly. The ratio between normal and affected calves corresponded to the 7:1 ratio expected in the experimental design used. It is therefore concluded that spinal dysmyelination is an autosomal recessively inherited defect. All cases in Denmark can be traced to a single American Brown Swiss bull.