A SURVEY OF INJECTION SITE LESIONS IN FED CATTLE IN CANADA

During November 1996 to January 1997, a survey was conducted at 5 Cana dian purveyors to measure the prevalence of injection site lesions in the top butt, boneless blade, outside round, inside round, and eye of the round. As trimmers were cutting these subprimals into steaks, tech nicians monitored each steak for grossly obvious scars. These scars we re trimmed, weighed, and scored as either a ''clear scar,'' ''woody ca llus,'' or ''cyst.'' All scars were subsequently examined histological ly and classified as a ''clear scar,'' ''woody callus,'' ''scar with n odules,'' ''mineralized scar,'' or ''cyst.'' Pieces were observed for broken needles while being processed and none were found. The estimate d prevalence of injection site lesions was 18.8% (95% CI, 16.4% to 21. 2%) in top butts, 22.2% (95% CI, 18.8% to 25.7%) in boneless blades, 4 .9% (95% CI, 3.6% to 6.3%) in the eye of round, 1.8% (95% CI, 1.1% to 2.9%) in the inside round, and 7.6% (95% CI, 5.6% to 9.8%) in the outs ide round. Some top butts originated from American fed cattle; the est imated prevalence of lesions was 9.0% (95% CI, 5.9% to 12.9%) in Ameri can top butts and 22.3% (95% CI, 19.4% to 25.3%) in Canadian top butts . The median weight of the lesions varied among subprimals and ranged from 64 g to 117 g. Histologically, 13% of the scars were clear scars, 47% were woody calluses, 5% were mineralized scars, 34% were scars wi th nodules, 0.2% were cysts, and 0.9% were normal fat infiltrations. A n economic analysis estimated an average loss of $8.95 per fed animal processed or $19 million dollars annually to the Canadian beef industr y from injection scars.