§ 54.103 - Classes of beef carcasses.

(a) Class determination of beef carcasses is based on evidences of maturity and apparent sex condition at the time of slaughter. The classes of beef carcasses are steers, bullocks, bulls, heifers, and cows. Carcasses from males—steers, bullocks, and bulls—are distinguished from carcasses from females—heifers and cows—as follows:

(1) Steer, bullock, and bull carcasses have a “pizzle muscle” (attachment of the penis) and related “pizzle eye” adjacent to the posterior end of the aitchbone.

(2) Steer, bullock, and bull carcasses have, if present, rather rough, irregular fat in the region of the cod. In heifer and cow carcasses, the fat in this region, if present, is much smoother.

(3) In steer, bullock, and bull carcasses, the area of lean exposed immediately ventral to the aitchbone is much smaller than in heifer and cow carcasses.

(b) Steer, bullock, and bull carcasses are distinguished by the following:

(1) In steer carcasses, the “pizzle muscle” is relatively small, light red in color, and fine in texture and the related “pizzle eye” is relatively small.

(2) In bullock and bull carcasses, the “pizzle muscle” is relatively large, dark red in color, and coarse in texture and the related “pizzle eye” is relatively large.

(3) Bullock and bull carcasses usually have a noticeable crest.

(4) Bullock and bull carcasses also usually have a noticeably developed small round muscle adjacent to the hipbone commonly referred to as the “jump muscle.” However, in carcasses with a considerable amount of external fat, the development of this muscle may be obscured.

(5) Although the development of the secondary sex characteristics is given primary consideration in distinguishing steer carcasses from bullock or bull carcasses, this differentiation is also facilitated by consideration of the color and texture of the lean. In bullock and bull carcasses, the lean is frequently at least dark red in color with a dull, “muddy” appearance—and in some cases it may have an iridescent sheen. Also, it frequently has an “open” texture.

(6) The distinction between bullock and bull carcasses is based solely on their evidences of skeletal maturity. Carcasses with the maximum maturity permitted in the bullock class have slightly red and slightly soft chine bones, and the cartilages on the ends of the thoracic vertebrae have some evidence of ossification; the sacral vertebrae are completely fused; the cartilages on the ends of the lumbar vertebrae are nearly completely ossified; and the rib bones are slightly wide and slightly flat. Bull carcasses have evidences of more advanced maturity.

(c) Heifer and cow carcasses are distinguished by the following:

(1) Heifer carcasses have a relatively small pelvic cavity and a slightly curved aitchbone. In cow carcasses, the pelvic cavity is relatively large and the aitchbone is nearly straight.

(2) In heifer carcasses, the udder usually will be present. In cow carcasses, the udder usually will have been removed. However, neither of these are requirements.