Many producers have observed unsightly injection-site lesions under the skin of calves after subcutaneous administration of clostridial vaccines. Beef quality assurance efforts throughout the last decade have strongly discouraged practices that cause intramuscular injection-site lesions. But beef quality assurance programs generally do not address lesions that form under the skin.
Researchers in Arkansas conducted a study on 37 weaned heifers to address this concern. All the heifers were administered a 2 cc dose of clostridial vaccine under the skin. Twenty-eight days later, each heifer was inspected for injection-site knots under the skin in the location the injection was administered. Injection-site knots were present in almost 65 percent of the heifers. The Arkansas researchers also measured blood serum antibody titers to compare the immune status of heifers with injection-site knots to those that were free of injection-site knots. Interestingly, the heifers that developed injection-site lesions under the skin had enhanced resistance to Clostridium chauvoei (commonly called Blackleg) at 28 and 84 days after the subcutaneous vaccine was administered. Plus, 28 and 56 days after the vaccine was administered, resistance to Clostridium sordellii (a sudden death disease) and Clostridium perfringens type D (commonly called overeating disease) was improved for heifers with subcutaneous injection-site lesions.
In general, the results of this Arkansas study indicate that resistance to clostridial diseases, as measured by antibody titers, is improved when subcutaneous injection-site lesions develop. This study indicates that lesions should not be a discounting factor when pricing cattle, but instead an indicator that cattle have been properly immunized.