CONTROL OF SOW MORTALITY BY CLOSTRIDIUM NOVYI VACCINATION IN ARGENTINA

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Agosto1 , M.; Corletti1 , G.; Fernandez2 , S.; Boix3 , O.
*Corresponding author (oriol.boix@hipra.com)
1 SuperPorco S.R.L., 2 Hipra Argentina, S.A., 3 HIPRA, Amer (Girona) Spain.

INTRODUCTION

One of the most common problems faced in the field is the increase in  sow mortality rates and therefore the economic impact that this  represents. It is not unusual nowadays to find mortality rates that  were considered unacceptable just a few years ago(1). Clostridium
novyi (Cl.noyvi) is an anaerobic, gram-positive and alpha  toxin-producing microorganism that causes porcine infectious  necrotic hepatitis(2). Sudden death in sows is commonly seen during  the peripartum period (near the end of gestation and during  farrowing)(3). The aim of this study was to evaluate the impact of  Cl.novyi immunization by using a commercial vaccine as a tool for the  prevention of sudden death.

MATERIALS AND METHODS

The present study was conducted on a farrow to finish farm of 1050  sows located in Entre Ríos, Argentina, after it had reported an increase  in the incidence of sow mortality. The average annual mortality rate in  2016 reached 8.48%. Cl.novyi presumptive diagnosis was made by  carrying out systematic necropsies in which macroscopic lesions  compatible with clostridium infections were found (enlarged liver,  emphysema, swelling of the abdomen,…). The entire farm was then  vaccinated and revaccinated, following the manufacturer’s  instructions, with SUISENG®, an inactivated vaccine containing E.coli
fimbrial adhesins, the LT toxin, Clostridium perfringens beta toxin and  Cl.novyi alpha toxin. The sow mortality rate was compared between  two different periods, namely Period A from January 2016 to April  2017, (non-vaccinated period) and Period B from May 2017 to
December 2019 (SUISENG® vaccination). Finally, a Wilcoxon test was  performed to compare the two periods.

RESULTS

Based on the historical data, the average monthly mortality rate  (Figure 1) was significantly decreased from 0.66% to 0.36% (Figure 2)  (p-value; 0.0021) after the immunization of the herd. This represents a  reduction of 45% in the mortality rate.

CONCLUSIONS AND DISCUSSION

These results suggest that on this farm, Clostridium novyi was one of  the main aetiological agents responsible for sow mortality. After the  implementation of a vaccination programme against the alpha toxin,  the mortality rate was significantly reduced(4). It is noteworthy that  good diagnostic tools to detect the presence of C.novyi may form a key  part of this process. Further studies should be performed to evaluate  the role of Clostridium novyi in problems of sudden death in sows.

REFERENCES

1. Sanz, M et al 2014. Assessment of sow mortality in a large herd
2. Popoff, M et al,. 2009
3. Songer G. 2012. Diseases of swine, 10th ed: 717-718
4. Seifert, H.S., et al., 1996.