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DR.RANDY JONES LIVESTOCK VETERINARY SERVICES PRRS CONTROL HAS IT CHANGED POST PCV2?
INTRODUCTION <ul><li>PRRS is still a major problem for producers worldwide </li></ul><ul><li>Control programs are varied i...
PRRS vs. PCV2 <ul><li>PCVAD replaced PRRS as disease #1 for a short period of time. </li></ul><ul><li>Controlling PRRS dur...
PRRS CONTROL CYCLE
PRRS CONTROL <ul><li>Breeding herd is where it all begins. </li></ul><ul><ul><li>Stop virus circulation </li></ul></ul><ul...
Key Points to Consider <ul><li>Immune Management of the Population </li></ul><ul><ul><li>Entire population must be exposed...
Key Points to Consider <ul><li>Management of Suckling Pigs </li></ul><ul><ul><li>Can be a continued source of virus even i...
McRebel <ul><li>Cross-fostering only allowed during the first 24 hours after birth.  (In severe breaks  no movement  allow...
Key Points to Consider <ul><li>Herd closure and replacement gilt management </li></ul><ul><ul><li>To eliminate the virus o...
What do I do now? <ul><li>I want a negative herd. </li></ul><ul><ul><li>Serial testing to be sure there is no virus circul...
What do I do now? <ul><li>I want to continue to immunize the herd  </li></ul><ul><ul><li>It is still very important that y...
 
PRRS CONTROL <ul><li>CONTROLLING PRRS IN THE GROWING PIG </li></ul><ul><ul><li>Clinically stable sow farms can still leak ...
Three-Site Production
PRRS  CONTROL <ul><li>What are the tools available? </li></ul><ul><ul><li>Ability to flow sites all-in all-out. </li></ul>...
KEY POINTS TO CONSIDER <ul><li>PRRS easier to manage in a 3 –site production system.  </li></ul><ul><li>One site farms pre...
KEY POINTS TO CONSIDER <ul><li>Vaccinating pigs for PRRS: </li></ul><ul><ul><li>Success depends on several factors </li></...
Monitoring is a Must
HOW DOES MONITORING HELP? <ul><li>You need to know the sow herd status and that of the pigs it is producing. </li></ul><ul...
Pooling samples will decrease PRRSv PCR sensitivity <ul><li>Pools of 3 reduce by 5% 3 </li></ul><ul><li>Pools of 5 reduce ...
Low prevalence herds need large numbers tested
Effect of Prevalence on Sample Size
HOW MANY SAMPLES? <ul><li>Must consider economics as well as accuracy </li></ul><ul><li>Statistical sampling is dependent ...
Summary <ul><li>PRRS Control is evolving as we better understand transmission and improve biosecurity. </li></ul><ul><li>W...
 
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Bi pre aasv health seminar jones ppt (1)

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Transcript of "Bi pre aasv health seminar jones ppt (1)"

  1. 1. DR.RANDY JONES LIVESTOCK VETERINARY SERVICES PRRS CONTROL HAS IT CHANGED POST PCV2?
  2. 2. INTRODUCTION <ul><li>PRRS is still a major problem for producers worldwide </li></ul><ul><li>Control programs are varied in scope and success. </li></ul><ul><li>Economic impact is believed to be $560 million a year in the United States. </li></ul>
  3. 3. PRRS vs. PCV2 <ul><li>PCVAD replaced PRRS as disease #1 for a short period of time. </li></ul><ul><li>Controlling PRRS during this period of time in growing pigs made PCVAD less severe. </li></ul><ul><li>Introduction of vaccines has practically removed PCV2 as a concern in the growing pig. </li></ul><ul><li>PRRS remains a major problem for producers </li></ul>
  4. 4. PRRS CONTROL CYCLE
  5. 5. PRRS CONTROL <ul><li>Breeding herd is where it all begins. </li></ul><ul><ul><li>Stop virus circulation </li></ul></ul><ul><ul><ul><li>Load herd with replacement animals </li></ul></ul></ul><ul><ul><ul><li>Homogenize herd immunity with vaccine </li></ul></ul></ul><ul><ul><ul><li>Close herd for an extended period of time. </li></ul></ul></ul><ul><ul><li>Continue immunity stimulation or allow herd to eliminate virus. </li></ul></ul><ul><ul><li>Monitor herd for evidence of virus circulation. </li></ul></ul>
  6. 6. Key Points to Consider <ul><li>Immune Management of the Population </li></ul><ul><ul><li>Entire population must be exposed at the same time </li></ul></ul><ul><ul><li>A booster 3-4 weeks later. Further stimulation and insurance for any animals not responding to the first exposure. </li></ul></ul><ul><ul><li>My preference is to use a modified live vaccine to manage the immune response to the infection. </li></ul></ul>
  7. 7. Key Points to Consider <ul><li>Management of Suckling Pigs </li></ul><ul><ul><li>Can be a continued source of virus even in a closed herd </li></ul></ul><ul><ul><li>Pigs can be born viremic or acquire infection from sows that are still shedding. </li></ul></ul><ul><ul><li>Moving these piglets or holding them back can perpetuate the infection. </li></ul></ul><ul><ul><li>A systematic approach to piglet management was developed by Dr. Monte McCaw – McRebel. </li></ul></ul>
  8. 8. McRebel <ul><li>Cross-fostering only allowed during the first 24 hours after birth. (In severe breaks no movement allowed until transplacental infection stopped) </li></ul><ul><li>Do not move sows or piglets between rooms </li></ul><ul><li>Eliminate nurse sows </li></ul><ul><li>Euthanize sick pigs that are unlikely to recover </li></ul><ul><li>Minimize handling of pigs. </li></ul><ul><li>No backward movement of pigs. </li></ul><ul><li>Stop all feedback if porcine tissue to pregnant animals. </li></ul>
  9. 9. Key Points to Consider <ul><li>Herd closure and replacement gilt management </li></ul><ul><ul><li>To eliminate the virus or viruses from the herd an extended herd closure must be done </li></ul></ul><ul><ul><li>200 days is an often mentioned critical time period for animals in the herd to clear infection. </li></ul></ul><ul><ul><li>Shorter closures can be successful but are a risk. Space and availability of off site breeding is a determining factor. </li></ul></ul><ul><ul><li>Some of the decision depends on your goal. If elimination is a goal then I would plan on a 200 day closure. </li></ul></ul><ul><ul><li>If clinical stability with continued immune management is the plan then a shorter time period may be considered. </li></ul></ul>
  10. 10. What do I do now? <ul><li>I want a negative herd. </li></ul><ul><ul><li>Serial testing to be sure there is no virus circulation. </li></ul></ul><ul><ul><li>Secure a naïve source of replacement gilts and semen </li></ul></ul><ul><ul><li>Isolate and blood test gilts prior to them entering the herd </li></ul></ul><ul><ul><li>PRRS Risk Assessment </li></ul></ul><ul><ul><ul><li>What are the risk factors for external virus exposure? </li></ul></ul></ul><ul><ul><ul><li>What are the risk factors for internal virus circulation? </li></ul></ul></ul><ul><ul><ul><li>How can I minimize these risks? </li></ul></ul></ul><ul><ul><li>Air filtration to stop exposure to new viruses has shown to be a very important tool in keeping negative herds free of PRRS virus. </li></ul></ul>
  11. 11. What do I do now? <ul><li>I want to continue to immunize the herd </li></ul><ul><ul><li>It is still very important that you prevent the introduction of new viruses. Herd immunity may not be complete enough to prevent infection of the herd. </li></ul></ul><ul><ul><li>Gilt replacement s need to be isolated and tested and then acclimated to herd that they are being added to. This can require at least 8 weeks of isolation/acclimation. </li></ul></ul><ul><ul><li>Monitor wean pigs for evidence of virus circulation. </li></ul></ul>
  12. 13. PRRS CONTROL <ul><li>CONTROLLING PRRS IN THE GROWING PIG </li></ul><ul><ul><li>Clinically stable sow farms can still leak virus. </li></ul></ul><ul><ul><li>Lateral infection in swine dense areas is a problem. </li></ul></ul><ul><ul><li>Continuous flow sites can perpetuate virus. </li></ul></ul><ul><ul><li>An immune pig from either vaccination or infection recovers and performs well on finisher. </li></ul></ul>
  13. 14. Three-Site Production
  14. 15. PRRS CONTROL <ul><li>What are the tools available? </li></ul><ul><ul><li>Ability to flow sites all-in all-out. </li></ul></ul><ul><ul><li>Partial depopulation of an infected site </li></ul></ul><ul><ul><li>Vaccination with uni-directional flow </li></ul></ul><ul><ul><li>Mass vaccination of population </li></ul></ul><ul><ul><li>Vaccination of pig flow prior to exposure to virus </li></ul></ul>
  15. 16. KEY POINTS TO CONSIDER <ul><li>PRRS easier to manage in a 3 –site production system. </li></ul><ul><li>One site farms present a challenge in getting virus circulation under control </li></ul><ul><li>Single sourcing pigs by air space is easier to manage than multi-source flows with different health status. </li></ul>
  16. 17. KEY POINTS TO CONSIDER <ul><li>Vaccinating pigs for PRRS: </li></ul><ul><ul><li>Success depends on several factors </li></ul></ul><ul><ul><li>Vaccinate entire population at same time </li></ul></ul><ul><ul><li>Vaccinate pigs prior to field exposure </li></ul></ul><ul><ul><li>Heterolgous protection </li></ul></ul><ul><ul><li>Virus strain differences </li></ul></ul>
  17. 18. Monitoring is a Must
  18. 19. HOW DOES MONITORING HELP? <ul><li>You need to know the sow herd status and that of the pigs it is producing. </li></ul><ul><li>If you are placing negative pigs on the finisher then serology can be used to determine when pigs seroconvert and with which virus. </li></ul><ul><li>Virus sequencing helps determine whether we have vertical transmission or lateral transmission. </li></ul>
  19. 20. Pooling samples will decrease PRRSv PCR sensitivity <ul><li>Pools of 3 reduce by 5% 3 </li></ul><ul><li>Pools of 5 reduce by 6% 3 </li></ul><ul><li>Pools of 5 reduce by 15.5%* </li></ul><ul><li>Pools of 10 reduce by 17.9%* </li></ul>3 : Rovira et al. 2007 *: Polson D. Personal Communication Pooling may dilute PRRSv and lead to false negatives
  20. 21. Low prevalence herds need large numbers tested
  21. 22. Effect of Prevalence on Sample Size
  22. 23. HOW MANY SAMPLES? <ul><li>Must consider economics as well as accuracy </li></ul><ul><li>Statistical sampling is dependent on the specificity and sensitivity of the test you are using. </li></ul><ul><li>Pooling of samples improves economics but can lower the sensitivity. </li></ul><ul><li>The prevalence can also affect your decision on sample size. </li></ul>
  23. 24. Summary <ul><li>PRRS Control is evolving as we better understand transmission and improve biosecurity. </li></ul><ul><li>We still struggle with how to properly immunize sows to protect them from new viruses. </li></ul><ul><li>Elimination of the virus from sow herds is a repeatable process. </li></ul><ul><li>Survivability of naïve or negative herds is still poor. New technologies will hopefully improve this. </li></ul><ul><li>Regional Eradication programs are underway in the United States </li></ul>

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