Modelling and Assessing Additional Transmission Routes for Porcine Reproductive and Respiratory Syndrome Virus: Vehicle Movements and Feed Ingredients

Mar 21, 2022

Abstract: Modelling and assessing additional transmission routes for porcine reproductive and respiratory syndrome virus: Vehicle movements and feed ingredients

Accounting for multiple modes of livestock disease dissemination in epidemiological models remains a challenge. We developed and calibrated a mathematical model for transmission of porcine reproductive and respiratory syndrome virus (PRRSV), tailored to fit nine modes of between-farm transmission pathways including: farm-to-farm proximity (local transmission), contact network of batches of pigs transferred between farms (pig movements), re-break probabilities for farms with previous PRRSV outbreaks, with the addition of four different contact networks of transportation vehicles (vehicles to transport pigs to farms, pigs to markets, feed and crew) and the amount of animal by-products within feed ingredients (e.g., animal fat or meat and bone meal). The model was calibrated on weekly PRRSV outbreaks data. We assessed the role of each transmission pathway considering the dynamics of specific types of production (i.e., sow, nursery). Although our results estimated that the networks formed by transportation vehicles were more densely connected than the network of pigs transported between farms, pig movements and farm proximity were the main PRRSV transmission routes regardless of farm types. Among the four vehicle networks, vehicles transporting pigs to farms explained a large proportion of infections, sow = 20.9%; nursery = 15%; and finisher = 20.6%. The animal by-products showed a limited association with PRRSV outbreaks through descriptive analysis, and our model results showed that the contribution of animal fat contributed only 2.5% and meat and bone meal only .03% of the infected sow farms.

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Video: You Be The Judge: Evaluating 8 Breeding Rams!

It's time for some honest feedback here at Ewetopia Farms! Today, we’re showing you all eight rams we used for breeding this year. Instead of just presenting them, we thought it would be fun to create a “Ram Report Card” — where we point out both their strengths and areas for improvement.

But here’s the twist: you be the judge! In the comments, let us know what you like about each ram and what you think could be improved. No ram is ever perfect, but every one of them brings something valuable to the flock. By sharing perspectives, we all learn more about what to look for in good breeding stock.

At Ewetopia Farms, we raise registered Suffolk and Polled Dorset sheep, focusing on high-quality genetics, structure, and friendly temperaments. Evaluating breeding rams is part of the bigger picture of building stronger flocks — and we’re excited to share the process with you.

If you enjoy seeing how we evaluate our animals, follow along by subscribing to our channel. We share daily insights into the joys and challenges of sheep farming here in Canada.