Reconsider the Depopulation and Repopulation Option
In the past year, both producers and veterinarians have experienced production and health challenges with pig flow due to interruptions from COVID-19, shuttered packing plants and changing market conditions. While many enterprises were fortunate to continue operations with varying degrees of impact, hasty decisions made under pressure might not have been ideal from a disease management perspective, especially porcine reproductive and respiratory syndrome (PRRS) elimination programs.
Among many challenges facing producers over the past year, the industry has seen rise to multiple new PRRS strains which have decimated impacted sow farms. Many of our industry elders refer to this winter’s dominant circulating PRRS strain as the worst they’ve ever seen. As PRRS viruses shift, veterinarians must have an open mind to shifting PRRS management and elimination strategies.
What is the Best Option?
With the producer’s goals in mind, PRRS viruses are managed or eliminated from farms using different control or eradication strategies. Historically, complete depopulation and repopulation in commercial sow herds has been considered as an extreme option to eliminate the PRRS virus. While this method is highly successful and provides producers and veterinarians with the most predictable elimination timeline, it is often the highest cost elimination method available. As is always the case, genetic farms have a different value proposition with the high value of their healthy animals versus the low value of infected animals. As such, multiplication herds that experience a PRRS break and need to return to high health status quickly due to downstream customer requirements for naïve breeding stock, are much more likely to find the cost of depopulation and repopulation palatable.
When considering depopulation in a commercial herd, it’s important to consider the impact of chronic health challenges with other endemic diseases such as mycoplasma hyopneumoniae or swine dysentery. These additional elimination candidates have a value proposition in addition to PRRS that should be considered in the overall financial implications. Elimination of several diseases at once and expected benefits in growing pig performance from decreased treatment costs and mortality quickly adds to the value proposition of a depopulation proposal.
In addition to health status benefits, producers also have the opportunity to invest in facility improvements such as filtration or pen gestation as well as technology upgrades in alarm systems or ventilation programs during facility downtime. There is also the opportunity to capture changes in genetics, correct parity structure and make flow adjustments.
While depopulation comes with the large costs of purchasing new breeding stock and an off-site breeding project, the recent increase in cull sow prices makes this option more economically feasible. Herds with an older parity structure and heavy sows are averaging $85/cwt in the current market. Marketing sows during this time period will help offset the cost of breeding stock. The relationship between cull and gilt prices is an ever-changing dynamic, but one producers should evaluate when looking at PRRS elimination options for their herd.
There are replacement gilts available from many genetic suppliers for producers looking to depopulate commercial herds. Discussion surrounding the current health status of the selected source should involve your herd veterinarian to familiarize yourself with any specific flow health challenges and expected performance.
Compounded frustration with the economic effects of chronic health challenges and devastating downstream losses from severe PRRS viruses, including the newly emerging PRRS lineage 1C variant, have incited a renewed interest in the depopulation and repopulation PRRS elimination approach, even among commercial herds.
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Depopulation: 4 Things Producers Need to Consider
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