Frequencies of Injection-Site Lesions in Muscles From Rounds of Dairy and Beef Cow Carcasses

The frequency of injection-site lesions in muscles from top sirloins and rounds in fed cattle carcasses is well documented; this study characterizes the frequency and severity of lesions in muscles from rounds of beef and dairy cow carcasses. Audits were conducted in 1998, 1999, and 2000 on 3190 rounds from cow carcasses. Outside round muscles were cut into 1.25-cm slices to characterize lesions. In 1998, 31% of beef rounds and 60% of dairy rounds had an injection-site lesion. Frequency of lesions in beef rounds significantly declined 5 percentage points between 1998 and 1999 and 6 percentage points between 1999 and 2000. The frequency of lesions in dairy rounds significantly declined 9 percentage points between 1998 and 1999 and 16 percentage points between 1999 and 2000. Frequencies of injection-site lesions in muscles of beef rounds were significantly lower than those in muscles of dairy rounds in all 3 yr. Injection-site lesions were most common between the hooks and pins of the hindquarter of beef cattle and between the pins and hocks of the hindquarter of dairy cattle. Clear lesions and woody calluses exceeded 89% and occurred more frequently than did other kinds of lesions in muscles of beef and dairy rounds in 1998, 1999, and 2000 audits. Of all injection-site lesions, between 3 and 5% were cystic in muscles of beef rounds, similar to the 2 to 4% of cystic lesions found in muscles of dairy rounds. Although yearly data indicate trends in declining frequencies of injection-site lesions, the need remains for educational programs and continued improvements in beef quality assurance practices among both beef and dairy producers.