Quantifying Individual Response to PRRSV Using Dynamic Indicators of Resilience Based on Activity

Lisette E. van der Zande, Jenelle R. Dunkelberger, T. Bas Rodenburg, J. Elizabeth Bolhuis, Pramod K. Mathur, W. James Cairns, Michael C. Keyes, John M. Eggert, Erin A. Little, Scott A. Dee, Egbert F. Knol

Research output: Contribution to journalArticleAcademicpeer-review


Pigs are faced with various perturbations throughout their lives, some of which are
induced by management practices, others by natural causes. Resilience is described
as the ability to recover from or cope with a perturbation. Using these data, activity
patterns of an individual, as well as deviations from these patterns, can potentially
be used to quantify resilience. Dynamic indicators of resilience (DIORs) may measure
resilience on a different dimension by calculating variation, autocorrelation and skewness
of activity from the absolute activity data. The aim of this study was to investigate the
potential of using DIORs of activity, such as average, root mean square error (RMSE),
autocorrelation or skewness as indicators of resilience to infection with the Porcine
Reproductive and Respiratory Syndrome Virus (PRRSV). For this study, individual activity
was obtained from 232 pigs equipped with ear tag accelerometers and inoculated
with PRRSV between seven and 9 weeks of age. Clinical scores were assigned to
each individual at 13 days post-challenge and used to distinguish between a resilient
and non-resilient group. Mortality post-challenge was also recorded. Average, RMSE,
autocorrelation and skewness of activity were calculated for the pre- and post-challenge
phases, as well as the change in activity level pre- vs. post-challenge (i.e., delta). DIORs
pre-challenge were expected to predict resilience to PRRSV in the absence of PRRSV
infection, whereas DIORs post-challenge and delta were expected to reflect the effect of
the PRRSV challenge. None of the pre-challenge DIORs predicted morbidity or mortality
post-challenge. However, a higher RMSE in the 3 days post-challenge and larger
change in level and RMSE of activity from pre- to post-challenge tended to increase the
probability of clinical signs at day 13 post-infection (poor resilience). A higher skewness
post-challenge (tendency) and a larger change in skewness from pre- to post-challenge
increased the probability of mortality. A decrease in skewness post-challenge lowered the
risk of mortality. The post-challenge DIOR autocorrelation was neither linked to morbidity
nor to mortality. In conclusion, results from this study showed that post-challenge DIORs
of activity can be used to quantify resilience to PRRSV challenge.
Original languageEnglish
Article number325
Number of pages7
JournalFrontiers in Veterinary Science
Publication statusPublished - 24 Jun 2020


  • resilience
  • accelerometer
  • dynamic indicator of resilience
  • activity
  • pig behavior


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