Title: Feasibility of Transdermal, Needleless Injection Device for Prevention of Pork Carcass Defects

A needle-free transdermal injection device was evaluated for effectiveness of vaccine delivery and for injection site lesions. A total of 96 pigs were vaccinated for pseudorabies virus (PRV) and for Mycoplasma hyopneumonia (M.hyo.). Pigs were divided into three groups; the first group served as unvaccinated controls, the second group was vaccinated with conventional hypodermic needles, and a third group was vaccinated with a needle-free, air powered injection device. Pigs were tattooed on the neck to mark the injection sites. Blood samples were collected from the pigs at 11-13 days and 23-25 days following injection and the serological response was measured. Injection sites were collected at slaughter and dissected to evaluate tissue damage. The results showed that both injection methods produced similar serological response in the vaccinated pigs and both were significantly greater than the controls. The injection site examinations have shown no lesions in any of the pigs. The results show the needle-free, transdermal injection device to be effective and safe. Elimination of needles will prevent residual needle fragments in carcasses and associated carcass defects from injection site lesions. Introduction Pork carcass defects resulting from intra-muscular injection of vaccines and antibodies are a well-recognized problem in the meat industry. Problems of abscesses and muscle damage are result of injections, but a more serious problem to the meat industry is the presence of broken needles and needle fragments. Needle fragments are not easily identified by metal detectors due to; alloy compositions of the needles, fragment size, and orientation to the detector. Needle fragments in pork carcasses, are identified by metal detectors in less than 10% of the cases, where they are present. Thus, the potential exposure of consumers to metal fragments in pork products is a serious