Dr. Bill Hollis - PRRS '174' virus - Field Experiences with Control and Management

PRRS 174 – Field Experience with Control and Management

William L. Hollis, DVMCarthage Veterinary ServiceCarthage, ILhollis@hogvet.com

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A Big Thank You ……

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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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A Big Thank You ……

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SHMP - System Analysis

The PRRS Reporting Group26 systemsOver 700 sow herdsOver 1.8M sows Approx. 30% of the industry

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HOW to apply the SHMP ResultsCarthage 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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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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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)

SHMP-4/24/15

PRRS virus cut patterns 2001 to 2010

PRRS virus cut patterns 2011 to 2014

SHMP-4/24/15

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In comes the Angry New Kid

SHMP-4/24/15

The “Virus Swarm” created by a dynamic population

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UMN Sequences over time

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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

SHMP-4/24/15

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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

SHMP-4/24/15

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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

SHMP-4/24/15

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More AcronymsTTBP = Time to Baseline ProductionTTS = Time to Stability (negative pigs)

SHMP 6/26/2015

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Can we shorten TTS

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

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

The Virus Swarm

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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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Production Controls

• AASV Website for Stages and Control

• www.aasv.org

AASV 2015 Lowe

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Production Controls

• Changes allowed when at to stage 2

AASV 2015 Lowe

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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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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!)

SHMP 8/21/2015

EWMA = exponentially weighted moving average = new breaks

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Correlation is NOT Causation• However……Much greater reporting of vaccine

use and 2v control programs in place

SHMP 8/21/2015

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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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Biosecurity Audit• People• Transport• Mortality Management• Supplies and Entry items• Maintenance

Then all the uncontrollable like …AIR….

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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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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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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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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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Management PracticeWean Down……WHAT?

• Plan ahead• No need when it is still BAD in gestation• Removes virus from farrowing• Must prepare WTM

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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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Management Impact

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July 2013 July 2014 July 2015

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Management Impact

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Herd 1 Herd 2

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Management Impact

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July 2013 July 2014 July 2015

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Management Impact

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July 2013 July 2014 July 2015

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Management Impact

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 250

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Herd 1Herd 2Herd 3Herd 4Herd 5

July 2013 July 2014 July 2015

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System Impact

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25Jul-13

Aug Sep Oct Nov Dec Jan-14

Feb Mar Apr May Jun Jul-14

Aug Sep Oct Nov Dec Jan-15

Feb Mar Apr May Jun Jul-15

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PED 40K pigs PRRS 20K pigs

Blue = Monthly production Red = Quarterly production Green = Difference from average

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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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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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A Big Thank You ……

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THANK YOU