Mycoplasma hyopneumoniae Eradication by Partial Depopulation and Strategic Medication with Vetmulin®

Benefits of M. hyopneumoniae eradication:

• Boost in technical performance
  • Improved feed conversion
  • Increased daily weight gain
  • Fewer days to reach market weight
  • Lower mortality rates
  • Decreased number of poor doing pigs
• Improvement in herd health status: reduced risk of porcine respiratory disease complex (PRDC)
• Increase in the market value of produced pigs
• High and fast return on investment
• Reduction of antimicrobial use and cessation of M. hyopneumoniae vaccination

Elimination of bacteria always requires the strict implementation of additional biosecurity measurements. Pigs free from M. hyopneumoniae need to be housed in completely emptied and thoroughly cleaned and disinfected units.

Two options for M. hyopneumoniae eradication:

1. Total depopulation and repopulation
   • Removal of all animals from the farm
   • More than 6 months loss of production and income
2. Partial depopulation and strategic medication
   • Only temporary depopulation of some farm sections without a stop in farrowing
   • Less disruption to cash flow
   • Maintenance of the parity profile and genetic potential of the sows
   • 90 - 95% success rate

Each farm is unique. Therefore, a farm-specific eradication program needs to be established.

Eradication protocol by partial depopulation and strategic medication: 3 steps

Step 1: Preparation

• Establishment of comprehensive biosecurity measurements. 
  • External: avoid re-introduction of the pathogen from outside the herd.
    
    • Purchase of pigs free from M. hyopneumoniae needs to be feasible in the future
    • Build or identify quarantine facilities
    • Implement a hygiene policy for trucks and visitors
  • Internal: avoid propogation of the pathogen in the herd
    • Establish a thorough cleaning and disinfection program
    • Optimize the flow of pigs: mycoplasma-free pigs must not be housed with (possibly) infected pigs in the same herd
• Eradication at times when the outside temperature is higher is preferred.
• Remove all weaned piglets older than 3-4 weeks until they reach 10 months of age to reduce the infection pressure in the unit as young pigs can actively shed the pathogen.
• Before starting the treatment protocol, the respiratory health status of the sows needs to be stabilized by removing all sick and unthriving animals and by stopping the introduction of new animals.

Step 2: Treatment

• Only animals older than 10 months (sows, gilts, boars) and suckling piglets stay on the farm and get treated with Vetmulin® (tiamulin):
  • Animals older than 10 months are medicated orally for 2 weeks: 6-8 mg tiamulin hydrogen fumarate/kg bodyweight/day (Figure 1). 
  • Suckling piglets are injected every 4 days for 3 weeks, starting 1 week earlier than the treatment of other animals: 1.5 ml/20 kg bodyweight (Figure 1). 

Figure 1. Illustration of staggered treatment program

Step 3: Post-medication period

• Pigs originating from sows that have already been treated for 2 weeks prior to farrowing are 'clean' and should be housed in 'clean' farms.
• Farrowing, weaning, grower and finisher facilities need to be emptied, thoroughly cleaned, and disinfected before the transfer of pigs free from M. hyopneumoniae. 
• Any purchased animals should be free from the disease.
• Success monitoring: diagnostic evaluation and confirmation of freedom from M. hyopneumoniae. 

Conclusion

Eradication of M. hyopneumoniae extensively improves animal health and technical performance. Enzootic pneumonia can be eliminated successfully by partial depopulation, comprehensive biosecurity measurements and medication with Vetmulin®.