Noh 1, H.; Byun 1, J.; Noh 1, S.; Choi 2, M.; Giralt 3, D., Álvarez 3, G.; Bernal *3, I.
1HIPRA Korea inc., 2Kwanghee Animal Hospital(Wanju, Korea), 3HIPRA, Amer(Girona),Spain
*Corresponding author: Ignacio.bernal@hipra.com
Introduction
Swine oedema disease, caused by verotoxin 2e (Vt2e) and known to induce degenerative angiopathy in pigs, has various impacts such as sudden death, neurological signs and retarded growth. Depending on the characteristics of the clinical signs, swine
oedema disease can be categorized into three types: clinical, chronic and subclinical types (1, 2). Recombinant Vt2e vaccine offers many benefits by preventing swine oedema disease. However, in the case of subclinical oedema disease where the manifestation is not obvious and non-specific, it is not easy to demonstrate the efficacy of the vaccine. The objective of this study was to assess the benefit provided by a recombinant Vt2e vaccine by analysing uniformity of slaughtered pigs before and after vaccination on a farm with subclinical swine oedema disease.
Materials & Methods
Swine oedema disease was confirmed on a Korean commercial farm with 600 sows (farrow to finish) by the detection of verotoxin- producing Escherichia coli (VTEC) using real-time PCR assay. The type of swine oedema disease on this farm was categorized as
subclinical due to the lack of specific symptoms, such as sudden death and neurological signs. To control the swine oedema disease, a vaccine with recombinant Vt2e antigen (Vepured®) was applied from January 2022, according to the manufacturer’s instructions. Data on the individual slaughtered animals such as the date of slaughter, carcass weight, thickness of backfat and grade of carcass were collected at the slaughterhouse from
January 2020 to September 2023. Considering the average days to market on this farm, 12,544 animals which were slaughtered from January 2020 to May 2021 were defined as the “Non-vaccinated” group and 8,419 animals which were slaughtered from June 2021 to September 2023 were defined as the “Vaccinated” group. To estimate uniformity by group, the coefficient of variation (CV) of carcass weight was calculated in both groups. Apart from uniformity, distribution of carcass quality grade of both groups was also analysed, following the standard laid down by the Korean Institute for Animal Products Quality Evaluation. For statistical analysis, linear regression model with group as a factor was performed for coefficient of variation and logistic regression with group as a factor was done for carcass quality grade.
Results
The coefficient of variation of carcass weight calculated for the“Vaccinated” group (6.82%) as lower than for the “Non-vaccinated” group (7.45%), with a statistically significant difference (P-value<0.0001) [Figure 1]. Regarding distribution of carcass qua- lity grade, the “Vaccinated” group showed a higher proportion of Grade 1+ and 1 (69.79%) compared to the “Non-vaccinated” group (61.76%), with a statistically significant difference (P-value=0.001) [Figure 2].
Discussion & Conclusion
The benefits achieved by controlling subclinical oedema disease can be estimated by using various parameters such as average daily gain and feed conversion ratio (3, 4). However, the results of this study show that other parameters that have not usually been
estimated, such as uniformity of animals or grade of carcass, can be also increased. As these additional improvements of parameters will be followed by increased profits on the farm, further study is needed to indicate the overall benefit of controlling subclinical oedema disease.
References
1. Natalia A. et al., Overview of the role of Shiga toxins in porcine edema disease pathogenesis, 2018
2. Clugston et al., Experimental edema disease of swine (E. coli entero-toxemia). 3. Pathology and pathogenesis, 1974
3. Scollo A, Mazzoni C. Edema disease vaccination in weaners improves feed conversion rate. In: Proceedings of: 9th ESPHM; 3-5 May 2017; Prague, Czech Republic; 2017. p. 365.
4. Daniel S. et al., Effect of the vaccination against Shiga toxin 2e in a farm
with history of oedema disease, caused by atypical Escherichia coli pro- ducing Shiga toxin (STEC), 2022
Code assign: BBD-PP-163
