Associations between health, productive performance and oral fluid biomarkers in commercial pig farms.

Background: Oral fluid contains analytes that may be reflective of health and welfare in pig herds. Additionally, oral fluid collection is a more convenient and cost-effective option when compared to blood sampling, increasing the potential of oral fluid as a non-invasive alternative tool. While a growing number of biomarkers can be measured in porcine oral fluid, the use of these analytes to compare commercial herds in veterinary practice is still limited. This study describes associations between oral fluid biomarker measurements and farm indicators of health and performance in 18 commercial farms.

Results: Using principal component analysis, three clusters of farms were identified, differing mostly in weaner and finisher mortality, daily gain and antimicrobial resistance. These groups were then compared in terms of oral fluid biomarker profiles. With regards to farm group (cluster), haptoglobin was higher in pigs from low-performing farms, especially when compared with pigs from high-performing farms (P = 0.01). Oxytocin tended to decrease in pigs from high-performing farms to low-performing farms (P < 0.10), while procalcitonin tended to be lower in pigs from high-performing farms compared to intermediate-performing farms (P = 0.07). Using regression trees, haptoglobin measured in late finishers was associated with weaner and finisher mortality. Further, high creatine kinase and low procalcitonin early after weaning were associated with low piglet mortality, whereas low daily gain was related to high alpha-amylase in late weaners and high creatine kinase in pigs at the start of the finisher stage.

Conclusions: Haptoglobin, procalcitonin, oxytocin, creatine kinase and alpha-amylase, measured in oral fluid, should be further studied as good candidates to assess pig herds and predict performance at a batch level, through a non-invasive approach. Herd performance and health figures at a particular time point are not always available and alternative measures, like oral fluid biomarker results, could be useful to anticipate health and welfare issues and adjust management.