THE MUSCLE-BONE RELATIONSHIP IN BEEF 1.2 L. E. ORME, :~ A. M. PEARSON, L. J. BRATZLER, W. T. ~,IAGEE AND A. C. WI,IEELER

W ITH the changes in market demands, there has been more and more emphasis placed on inherent muscling and freedom from excessive fatness in beef. Therefore, an objective index of muscling either in the live animal or carcass would be extremely useful. The cannon bones have been studied as to their possible relationship to early maturity and degree of muscling. Hammond (1932) and Palsson (1939, 1940) reported that thickness of bone is directly associated with breed improvement for in- creased meat production and early maturity. Hirzel (1939) reported that shortening and thickening of the cannon is associated with a thickening and shortening of muscle covering in sheep. Concerning the cannon bone: muscle ratio, McMeekan (1956) stated, "So strong is this relationship that the weight of muscle could be determined within one percent if the weight of the cannon bones are known." He also stated that the finer boned animals have a smaller amount of lean tissue and a larger amount of fat than the heavier boned animals on a percentile basis. The data of Wythe (1958) on 28 steers indicated that a significant positive relationship existed between bone thickness and muscling. The use of measurements taken of the spinal processes as a possible index to muscling has been investigated previously. Ljungdahl (1942) measured the spinous processes of the shoulder, rack and loin of lambs and found that the lengths of the several processes were not closely related to the weights of the respective wholesale cut. This study was undertaken to determine the usefulness of using various measurements of cannon bones and those taken from radiographs of the lumbar region of the vertebrae as a possible index to total muscling in beef cattle.