Limbs flexed. A sub-lethal hereditary factor, simple recessive, in Zebu Gir and Indubrasil

Abstract

The article describes a sub-lethal hereditary defect related to a single recessive factor that occurs in the Gir and Indubrasil cattle. The defect is represented by the flexed pasterns of new borns calves. The intensity of the defect is variable. In more severe cases the knees articulations are seldom flexed. In this cases the animals can not stand upright and in less severe ones the calves stand but with difficulty. The restablishment is rare and the calves severely afflicted can not live without the aid of the man since they need assistence. 25 cows that produced defective calves and 13 bulls in the same condition were studied. These animals were classified as carriers of recessive factor. The author examined the pedigrees of all defective animals and found out that without exception all were descendents of parents that possessed at least once carrier ascendents. Non-carrier cows descendent from non-carrier ascendents, bred with carrier bulls did not produce calves with the defect. The author discusses in the end the measures necessary to decrease the percentage of the number of defective calves in the herd.