Incidence of injection-site lesions in beef top sirloin butts.

Damaged beef muscle tissue resulting from intramuscular injections of animal-health products represents a "quality control" problem and an economic loss to the beef industry. Fifteen individual and sequential national audits of injection-site lesions in beef top sirloin butts have been conducted at the steak provisioner/cutting level between November 1995 and July 2000. The national incidence of injection-site lesions in top sirloin butts (n = 240,080) decreased (P < 0.05) between November 1995 (11.4%) and July 2000 (2.1%). From November 1995 to July 1997, mean weight per injection-site lesion, across all lesion classes, increased (P < 0.05) from 192.5 g to 435.8 g, respectively; mean weight per lesion subsequently decreased (P < 0.05) to 249.8 g in July 2000 but was still heavier (P < 0.05) than in November 1995. Results of these audits suggest that producers have changed injection practices. These changes have likely been in response to educational efforts, such as those made by National Cattlemen's Beef Association and through state beef quality assurance programs. Analyses of results for lesion classes, partitioning lesions according to chronological stages of the healing process, suggested that the majority of lesions were induced at times that coincide with cow-calf, stocker, or early finishing-period stages of cattle production.