Three replicates of 24 individually-penned boars, 5.5 months to 4 years in age, were evaluated. Oral fluid samples were collected on ropes were soaked with a solution of sucrose and apple juice and subsequently dried. To familiarize the animals to the collection process, boars were first allowed to investigate ropes placed on the floor of the pen. Thereafter, ropes were placed in “rope holders” fixed at the front of each pen for ≤ 20 minutes and oral fluids were deposited as the boars interacted with the rope. To collect oral fluid specimens, the bottom 6 inches (wet end) of the rope was inserted into a re-sealable plastic bag and cut. The plastic bag with the rope inside was then compressed to extract the maximum amount of fluid for decantation into a tube. Oral fluid samples were collected daily for 7 days prior to inoculation with PRRSV and for 21 days afterwards. Trial One boars were inoculated with commercial PRRS vaccine, Trial Two with a Type 1 PRRSV isolate, and Trial Three with a Type 2 PRRSV isolate. Serum was obtained on DPI -7, 0, 7, 14, and 21 on all boars. Four randomly selected boars were also bled on DPIs 3, 5, 11, and 17.
Summary of results
Seventy of 72 boars were successfully trained for oral fluid collection. Each replicate had a total of 696 potential samples (29 days × 24 boars). In Trial One, 690 samples were collected resulting in 99.14% success rate; in Trial Two, 596 samples were collected resulting in 85.63% success rate; in Trial Three , 668 samples were collected resulting in 95.9% success rate. The average amount of fluid collected for each replicate the reps were 16.1mL, and 15.0mL, and 15.8mL, respectively. The efficiency of sample collection by age was cull 85.6%, and selects 95.8%. These results suggested that it would be more efficient to train boars in isolation before being placed into the study.
Oral fluid samples can be quickly and easily collected from most boars. Studies in progress will evaluate the use of oral fluid samples for PRRSV monitoring. This approach may prove to be an animal- and labor-friendly approach to monitoring individually-housed adult animals (sows and boars) for PRRSV and other infectious diseases.
J. Johnson; M. Engle; A. Kittawornrat; D. Whitney; C. Olsen; J. Prickett; T. Schwartz; K. Schwartz; J. Zimmerman. Oral fluid collection from individually-penned, PRRSV-infected boars. 2010 AASV Annual Meeting: Implementing Knowledge: 312.