Relationship of body measurements to genotypes for bovine dwarfism as estimated from X-ray of the lumbar vertebrae

The apparent increase in frequency of this type of dwarfism suggests that normal animals heterozygous for this hereditary characteristics favored in the selection of breeding stock. The characteristics leading to this possible selective advantage are not known. Recent emphasis in research on the problem has been directed toward finding some means of distinguishing normal homozygous (non-carrier) from normal heterozygous (carrier) cattle. In cooperation with Iowa State College, studies of X-ray pictures of the lumbar vertebrae of young calves were made at the University of Tennessee in an effort to make this distinction. Assuming the X-ray was correct in distinguishing carrier from non-carrier calves, body measurements were made of the calves X-rayed in an effort to make a similar and cheaper distinction. The purpose of this paper is to present a parietal analysis of the data collected in Tennessee during 1954 in connection with this study.