1) The document discusses strategies for managing a PRRS virus strain called PRRS 174, which has caused severe issues in many infected herds. 2) Key recommendations include limiting virus spread by controlling gilt introductions and piglet movement, monitoring herd progress, and creating action plans tailored to the herd's stage of infection. Vaccination of gilts, sows, and piglets is also advised. 3) Management practices like stopping all piglet movement, conducting a "wean down" to remove virus from farrowing, and increased piglet monitoring can help control the virus and minimize impacts on production.

1. PRRS 174 – Field Experience
with Control and Management
William L. Hollis, DVM
Carthage Veterinary Service
Carthage, IL
hollis@hogvet.com

2. 1
A Big Thank You ……

3. PRRS 174
• Outline
– It is bad
– There are things you can do
– You have to plan ahead
– Action is better than Reaction
– Future direction
• Summary
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4. 4
A Big Thank You ……

5. SHMP - System Analysis
The PRRS Reporting Group
26 systems
Over 700 sow herds
Over 1.8M sows
Approx. 30% of the industry
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6. HOW to apply the SHMP Results
Carthage System
– Location controls (Area spread)
Client herd system 30,000 sows
– Within herd management (TTS and Controls)
Client herd individual herd 3000 BTW
– Herd level immunity (Monitoring)
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7. PRRS
…are we speaking the same language?
• Stages based on BTW Herd and Piglets
• 1 = ACTIVE
• 2 = Stable positive (2v = with vaccine)
• 3 = Introducing naïve gilts
• 4 = Confirmed naïve population
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8. PRRS
…are we speaking the same language?
• RFLP Cut Pattern – what’s in a name?
• 252……MLV vaccine like
• 184…..used to be the bad boy
• 174…..angry new kid on the block
• Honest answer is both “Virus Swarm” and a
mix of immune response to that swarm
– Multiple PRRS virus changes over time
– Multiple levels of immune status (gilts, sows, piglets)
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9. SHMP-4/24/15
PRRS virus cut patterns 2001 to 2010

10. PRRS virus cut patterns 2011 to 2014
SHMP-4/24/15

11. In comes the Angry New Kid
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SHMP-4/24/15
The “Virus Swarm”
created by a dynamic
population

12. UMN Sequences over time
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13. PRRS 174
• Strain first started wreaking havoc approximately
1 year ago
• Strain appears to evolved from the 1-8-4 family of
PRRS viruses
• Causes severe clinical signs in most infected
herds including elevated sow mortally,
reproductive disease and pre-weaning mortality
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SHMP-4/24/15

14. PRRS 174
• Decrease performance including up to
50% mortality observed in growing pigs
• Detected in sow herds that are solidly
vaccinated and or have immunity from recent
infection with other PRRS strains
up to 70% pregnancy loss reported
• Virus is certainly explosive when introduced
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SHMP-4/24/15

15. PRRS 174
• Concern that time to achieve stability is longer
than expected and there may be a higher
recurrence rate in sow herds previously
thought to be “stable”
• Response to interventions has been varied
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SHMP-4/24/15

16. More Acronyms
TTBP = Time to Baseline Production
TTS = Time to Stability (negative pigs)
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SHMP 6/26/2015

17. Can we shorten TTS
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SHMP 6/26/2015
Logical duration before stability must include complete duration of gestation
…at least 20 weeks to farrow piglet born to mothers after stability is achieved

18. PRRS 174 – WHAT TO DO
• What creates the dynamic population?
– Gilt introduction
– Piglet fostering
– Needle pokes
– Piglet handling
– Water troughs…..
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The Virus Swarm

19. PRRS 174 – What to do
• Limit the virus desire to create the “Swarm”
– What we can control
• Gilt introductions
• Piglet movement
• Monitor progress
– Create actions based on stages
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20. Production
Controls
• AASV Website for
Stages and Control
• www.aasv.org
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AASV 2015 Lowe

21. Production
Controls
• Changes allowed
when at to stage
2
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AASV 2015 Lowe

22. Plan Ahead – “What we can Control”
• DAY 1 PRRS ACTIVE
– STOP piglet movement
– Cull aggressively to make space for gilts?
– Prepare to LOAD and CLOSE to new gilts
– Euthanize severe ill piglets
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23. Plan Ahead – “What we can Control”
• Vaccination with Modified Live PRRS vaccine
– Gilts naïve to begin with
– Gilts two doses 30 days apart
– Sow herd annual immunity
• (Remember Oct 15th happens every year!)
23
SHMP
8/21/2015
EWMA =
exponentially
weighted
moving average
= new breaks

24. Correlation is NOT Causation
• However……Much greater reporting of vaccine
use and 2v control programs in place
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SHMP
8/21/2015

25. Client System impact 22,000 sows
• 7 sow herds in Iowa all become POSITIVE
– Virus Introduction = Biosecurity Actions
– Virus Control = Production Actions
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26. Biosecurity Audit
• People
• Transport
• Mortality Management
• Supplies and Entry items
• Maintenance
Then all the uncontrollable like …AIR….
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27. Client System strategy for Control
• Vaccine
– Herd Stability
– Gilt Stability
– Piglet control
• LVI – WHERE anticipated “Swarm”
• Management practice
– STOP piglet movement
– Plan for a “Wean Down”
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28. Vaccine
• Sow herd immunity
– Mass vaccination with focus on winter
– No needle change
• Gilts 2x - 30 days apart in development
– Arrive naïve in off site finishers
• Piglets
– When you are in stage 1 consider piglets too
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29. LVI…..no more….
• Live Virus Inoculation…only used in initial
– After vaccine or in vaccinated herd
–Dr Linhares 2014 : creates higher piglet losses
– Faster TTS but comes at a cost
• Oral or Injection
• Gilts vs Sows
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30. Management Practice
• STOP pig movement immediately
• No movement even at birth
• Needle change every litter
• Boot change into newborns
• Weaned pig movement in hall
• Washing rooms change clothes
• Staff allocation to newborns
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31. Management Practice
Wean Down……WHAT?
• Plan ahead
• No need when it is still BAD in gestation
• Removes virus from farrowing
• Must prepare WTM
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32. Management Practice
• Euthanize poor pigs prior to 10 days age
• “Wean Down”
– When 90% of litters have 10+ pigs at 10 days age
– When a natural gap in the farrowing flow occurs
– Wean all pigs 14 days and older
– Clean up large portion of farrowing
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33. Management Impact
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Herd 1
July 2013 July 2014 July 2015

34. Management Impact
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35. Management Impact
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36. Management Impact
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July 2013 July 2014 July 2015

37. Management Impact
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
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July 2013 July 2014 July 2015

38. System Impact
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Jul-15
PED 40K pigs PRRS 20K pigs
Blue = Monthly production Red = Quarterly production Green = Difference from average

39. What about PRRS Impact on WTM?
• Of course PRRS is harder on WTM than PEDV
With PRRS….Clean up of farrowing is
the BEST and FIRST solution to better
pigs for WTM
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40. Lessons for Future Control
• Increase piglet monitoring
– When setting management practices
– STOP moving pigs when it is bad
– Create ACTION PLAN for your herd
• PRRS Piglet vaccine in lactation
– When you anticipate activity
• Establish a gilt action plan
– Both for Stage 1 to 2 back if needed
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41. 41
A Big Thank You ……

42. THANK YOU
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