Porcine Respiratory and Reproductive Syndrome (PRRS) control in 6 Farrow to Finish (FF) herds: Benefit of whole herd approach

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INTRODUCTION

Infection with Porcine Reproductive and Respiratory Syndrome virus (PRRSv) is causing reproductive disorders on sows and respiratory clinical signs on growing pigs. It is one of the most costly diseases in the swine industry1. PRRS control remains a challenge. The aim of this study was to evaluate the benefit of a whole herd approach using the “5-step” process, which was developed by Boehringer Ingelheim (BI)2, to control PRRS in 6 French FF herds.

MATERIAL AND METHODS

Six FF herds, with a confirmed circulation of PRRS virus, were included in this study. Before inclusion, 4 out of 6 herds vaccinated the sows with MLV vaccines other than BI vaccines (mass or batch vaccination). None of the herds vaccinated the growing pigs. In each farm, the 5-step process (Table 1) was applied and a specific action plan was implemented including biosecurity measures and MLV vaccination. All the herds were mass-vaccinated (sows with Reprocyc® PRRS EU and growing pigs with Ingelvac PRRSFLEX® EU) twice, 4 weeks apart. Then, the sows were mass vaccinated every 3 months and a batch vaccination was implemented on growing pigs, between 4 and 7 weeks of age. The PRRS status of each herd was evaluated according to the AASV guidelines3 . The reproductive and growth performances were assessed by recording batch data.

Table 1. “5-step” process

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RESULTS

In most farms, the breeding herd remained positive and stable. One farm evolved from an “instable” to a “stable” status. Regarding the growing pigs, the status improved in most of the herds. Globally, the reproductive performances improved with a significant increase of weaned piglets per sow in 5 farms (Table 2). The growing performances improved as well with a significant increase of the wean to slaughter Average Daily Gain (ADG) in 2 farms. The standard deviation for ADG was reduced in 5 farms (Table 3).

Table 2a. Reproductive performances / Pregnancy rates

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Table 2b. Reproductive performances / Prolificacy parameters

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Table 3. Growth performances

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CONCLUSION AND DISCUSSION

This study showed the benefit of the implementation of the “5-step” approach in 6 FF farms. The improvement of reproductive performances might be related to the change of the current MLV vaccine to Reprocyc® PRRS EU and/or the change of the vaccination protocol (from batch to mass vaccination). Moreover, the implementation of the MLV vaccination in growing pigs might have indirectly contributed to a beneficial effect by decreasing the overall infection pressure in such FF herds. Finally, the implementation of biosecurity measures that were recommended during the “5-step” process, probably played an important role in the increase of the reproductive performances. Overall, the wean to slaughter ADG increased (+38g) with disparities between herds. The herds without improvement of ADG were either co-infected with other pathogens such as PCV2 or showed management procedure at risk (e.g.: increase of the pig load per pen following the increase of prolificacy). Nevertheless in all herds the standard deviation decreased (-7.2g) indicating a better homogeneity of slaughtering pigs.

REFERENCES

  1. Nathues H. et al, Preventive Veterinary Medicine, 2017
  2. Rathkjen PH et al. J Microb Biochem Technol 2018
  3. Holtkamp D. J. et al, Journal of Swine Health and Production, 2011
  4. Messager I. et al., ESPHM 2018