Paisley Canning from South West Ontario Veterinary Services, Oral Fluids For Monitoring In Suckling Pigs

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The use of oral fluids as a diagnostic sample in  group-housed  nursery,  grow-finish,  and breeding  stock  has  been  quite  rapid.  Oral fluids  from  due-to-wean  litters  could  be  a valuable   tool   in   monitoring   pathogens   and predicting the health status (eg PRRS, IAV) of pig populations post-weaning. Samples can be collected from suckling piglets that are near weaning age but getting  suckling  pigs  to  consistently  chew  on  the ropes  has been a challenge in  achieving  consistent results.  Family  oral  fluid  (FOF)  sampling  involves placing the rope so that both sows and their litters have  access  to  the  rope.  Litter  oral  fluid  (LOF) sampling makes the rope available to the litter only. Almeida et al reported an approximate 73% success rate  when  collecting  family  oral  fluid  samples versus  44%  success  when  collecting  only  from litters.  From  a  collection  of  72  family  oral  fluid samples and matching sera from 718 piglets, 84.4% (27  of  32  litters)  were  PRRSV  RT-PCR  positive while 24.2% (174 of 718 piglets) of serum samples were positive for PRRSV nucleic acid.

 

The  objective  of  this  study  was  to  determine  the optimum procedure for collecting oral fluid samples from  due-to-wean  litters.  Successful  collection  of oral  fluids  from  due-to-wean  litters  using  “Litter Oral  Fluid”  (LOF)  or  “Family  Oral  Fluid”  (FOF) sampling  techniques  were  compared  in  4  phases involving 920 attempts to collect oral fluids.

  • Phase 1 testing showed that prior exposure to a rope  improved  the  success  rates  of  both  LOF (33.4%) and FOF (16.4%) techniques.
  • Phase  2  determined  that  longer  access  to  the rope (4 h vs 30 min) did not improve the success rate  for  either  LOF  or  FOF.  No  need  to  wait longer  than  30  minutes  expecting  a  different outcome.
  • Phase  3  evaluated  the  effect  of  attractants  and found  that  one  (Baby  Pig  Restart®)  improved the  success  rate  when  used  with  the  FOF technique.
  • Phase  4  compared  the  success  rates  of”optimized  LOF”  (litters  previously  trained)  vs “optimized  FOF”  (litter  previously  trained  and rope  treated  with  Baby  Pig  Restart®)  vs standard FOF.

The  researchers  found  there  was  no  difference between  the  FOF-based  techniques,  but  both  were superior to the “optimized LOF” technique

Take Home Message

Family  oral  fluid  based  procedures  provided  a significantly higher probability of collecting oral fluids  from  due-to-wean  litters  (mean  success rate 84.9%, range 70% to 92%) when compared to  LOF-based  methods  (mean  success  rate 24.1%, range 16.5% to 32.2%).

Submitted by Paisley Canning, DVM

Ref:Almeida  MN,  Rotto  H, Schneider P,  Robb  C,  Zimmerman  JJ, Holtkamp DJ, Rademacher CJ, Linhares DCL.Collecting oral fluid samples  from  due-to-wean  litters.  Prev  Vet  Med.  2019  Nov 4;174:104810.  doi:  10.1016/j.prevetmed.2019.104810.  [Epub  ahead of print]

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