ANIMAL HEALTH Genetic

Congenital defects or diseases are abnormalities of structure or function present at birth. In cattle many of these defects of either genetic, environmental, or unknown cause—or due to environmental-genetic interaction—have been identified. The genetically caused diseases are mostly due to homozygosity of a simple autosomal recessive gene, meaning that the animal has received one defective gene from each of its parents. It is desirable to recognize congenital defects which are of significance to cattle owners and breeders. Not only is di= agnosis important, but methods to control genetically induced defects should be available. The most frequently encountered defects seem to