The first objective of this project was to determine the current state of practice of injection methods on swine farms as reported by swine veterinarians. For breeding animals, the neck was the most common site of injection for except for hormones in sows, where perivulvar injection was the most common (67%). Thirty-eight percent of respondents reported the hip as an injection location in sows. For growing pigs, the neck was the most common site of injection (>99%). Twenty-five and 8 percent of respondents reporting using needle-free injection in breeding animals, and growing pigs respectively. Forty-percent reported using detectable needles. Eighty-seven percent had a protocol to identify animals that had a physical hazard. Seventy-seven percent inform the packer of potential physical hazards, and 38% had been contacted by packer regarding physical hazards or abscesses associated with injection sites.

The second objective of this project was to describe and estimate the prevalence of carcass defects of market swine and cull sows at slaughter. Each of 3 market hog plants was visited 3 times over a 1 year period (total of 9 sample periods) to complete a cross-sectional survey. A total of 4000 market swine carcasses were visually observed for presence of defects. Of all market swine carcasses, 97.5% had no lesions, 2.2% had a neck lesion, 0.15% a hip lesion and 0.08% prevalence each for shoulder, perivulvar and ham regions. One pig had 2 lesions (neck and shoulder). There were no significant differences between market hog plants in the prevalence or distribution of lesions. Each of 3 cull sow plants was visited 3 times over a 1 year period (total of 9 sample periods) to complete a cross-sectional survey. A total of 3200 sow carcasses were visually observed for presence of defects. Of sow carcasses, 84.9% had no lesions, 11.2% had a neck lesion, 2.7% had a lesion on the hip, 0.3% ham, 0.6% perivulvar, 0.06% loin, 0.6% shoulder, and 0.5% of sow carcasses had 2 lesions. There was a significant difference in prevalence of lesions between plants. For the presence of any lesion the prevalence was 11.1%, 24.2% and 7.6% for the three plants (χ2df=2, p<0.001). The plants differed in the prevalence of lesions at different locations on the carcasses. The prevalence of neck lesions was 6.1%, 21% and 4.3% for the three plants (χ 2df=”2,” p<0.001). The prevalence of hip lesions was 3.7%, 1.8% and 2.4% for the three plants (χ 2df=”2,” p<0.05). The prevalence of lesions in the perivulvar, ham and shoulder regions were also different between plants (χ 2df=”2,” p<0.05).

This is the only description of injection technologies used in swine. The data suggests a very low prevalence of carcass defects in the market swine population studied, as well as a consistency of distribution of defects (which suggests standardization of injection practices) among farms raising growing swine. Furthermore, the defects are located in the most commonly recommended location for injection (neck) by the National Pork Board Pork Quality Assurance (PQA Plus) program. In contrast, lesions associated with injection sites in cull sows were higher and more variable between plants, suggesting that the use of alternate injection sites identified in the survey are contributing to lesions in injection sites not specifically recommended by the PQA Plus program, specifically in the hip and shoulder region.

Questions about this study can be directed to C. Scanlon Daniels, DVM, MBA, Circle H Headquarters, LLC, PO Box 1150, 3216 US Hwy 54 East, Dalhart, TX 79022. Email: [email protected] Phone: (806) 244-7851 Web: www.circleh.info