Reduction in Lesion Incidence in Pork Carcass Using Transdermal Needle-free Injection of Foot-and-Mouth Disease Vaccine

Abstract

Foot-and-mouth disease (FMD) is an infectious disease affecting pigs. The control of FMD in swine husbandry is very important because its outbreak results in a vast economic loss. FMD vaccination has effectively controlled FMD; however, it results in economic loss associated with the incidence of lesions in the pork meat at the injection site. The objective of this study was to investigate the effects of transdermal needle-free injection (NFI) of the FMD vaccine on the incidence of lesions at the injection site. Pigs (n=493) in the control group were vaccinated with the FMD vaccine using a commercial syringe needle, while 492 pigs in the transdermal NFI group received the FMD vaccine using a needle-free gas-powered jet injector. After the slaughter of the pigs, the incidence of lesions at the injection site of all pigs was checked by plant workers. The result of this study showed that the incidence of lesions in the pork ham from pigs vaccinated with NFI was 14.82% lower than that in control pigs (p<0.01). In addition, lesions generated in the NFI group were found just in the subcutaneous tissue. Therefore, the incidence of lesions at the injection site in pork from pigs vaccinated with the FMD vaccine can be effectively reduced by using transdermal NFI rather than a conventional syringe needle.

Welfare Benefits of Intradermal Vaccination of Piglets

“…Besides representing a substantial economic loss, the presence of tissue damage at the site of injection in pig carcasses is an indicator that pain occurred. Contrary to Houser et al [ 21 ] who did not report a significant difference in carcass lesions between vaccination methods, carcass defects (such as granuloma, abscess, and fibrosis) resulting from intramuscular injections of vaccines have been reported in some studies [ 24 , 25 ]. Needle-free injections might be expected to prevent possible tissue damage and bacterial contamination caused by needles.…”

Reducing lesion incidence in pork carcasses by heating foot-and-mouth disease vaccine before injection

“…The incident rate of lesions on the pork butt (vaccination site) was 21.70% in the control group (Figure 1). This value is higher than 19.17% of a previous study [11]. In the present study, the FMD vaccine was injected in the neck, while the [23] and three types of hypothetical farm size are assumed: farms with 100, 500, and 1,000 sows.…”

“…Cho et al (2020) Asian-Australas J Anim Sci 33:634-639 vaccination site was the ham in the previous study [11]. Ko et al [2] found that the incident rate of lesions differed with different sites of injection, and it was higher in the neck than in pork ham.…”

“…The lesion incidence at the vaccination site in animals is known to occur due to tissue damage and contamination caused by the needle [8]. Recent studies reported that the use of needle-free injection devises instead of needle syringes for vaccination of pig resulted in the increase of pork quality by reduction of muscular lesions with the inhibition of muscle damage [10,11]. However, the adaptation of needle-free injection devises in farms is costly because of the expensive devise, training of a worker, and maintenance [10].…”

“…Farms that rear 1,000 sows can benefit from 1,863,289 KRW (1,600 USD), in one year, when they adopt heat treatment of the FMD vaccine before injection. Ko et al [11] reported that the use of a transdermal needlefree injection for FMD vaccination effectively reduced the incidence rate of lesions in pork carcasses from 19.17% to 4.35%. However, the needle-free injection requires a high [10].…”