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]