The hidden cost of pests in swine production

For modern swine operations, pest management is no longer a background task; it is a direct driver of profitability. In a system where margins are tight and performance is closely monitored, even minor disruptions from pests can have significant downstream effects. If you’re seeing flies, off-feed pigs, or frustrated staff, pest pressure is already impacting performance—and costs.

 

What often looks like a small irritation issue is already affecting feeding behavior, labor efficiency, and daily operations.

 

The hidden impact on feed efficiency and growth

Lice, mites, and flies do more than irritate pigs; they disrupt growth. As Tony Morris, Director - Regional Sales, Swine for MWI Animal Health explains, “It’s almost a distraction that keeps pigs from going to the feeder and really affects their efficiency at which they grow and convert.”  

 

What to watch for

• Pigs off feed
• Restlessness or rubbing
• Reduced time at the feeder
  
  

What it means

• Likely parasite pressure (lice or mites) disrupting feeding behavior
  
  

What to do

• Inspect animals immediately
• Treat affected groups without waiting for visible confirmation
  
  

This constant irritation reduces feed conversion efficiency and slows weight gain.

While pest-related losses may seem minor individually, they quickly scale across an operation. According to Morris, each pest can cost up to a couple dollars per head. Across an entire barn or system, those small losses can determine overall profitability.

 

Operational and workforce disruptions

The impact extends beyond the animals. Certain pests create immediate disruptions.

Fruit flies overwhelm barns, making it difficult for employees to work comfortably. Dr. Mike Catangui, Manager- Entomology Integrated Technical Services, MWI Animal Health notes, “The workers can’t even open their mouths. They don’t want to be in that building.” That kind of pest pressure affects not just comfort, but daily workforce efficiency and willingness to remain in affected spaces.

Indian meal moths clog feed delivery systems, interrupting feeding. When pests interfere with feed movement, the consequences can extend beyond inconvenience to lost intake, disrupted routines, and broader production risk.

 

The pests that matter most in swine production

Not all pests pose the same risks. Understanding their roles is key to effective control. Some primarily threaten animal and human health, some undermine feed efficiency and gain, and others create costly operational problems. Knowing which type of pressure you are dealing with is the first step toward choosing the right response.

• High-risk disease vectors: House flies and roaches spread pathogens that affect both swine and humans, making them significant biosecurity risks.
• Performance-impacting parasites: Lice and mange mites cause constant irritation, leading to stress, reduced feed intake, and poor feed efficiency.
• Seasonal economic pests: Mosquitoes and flies peak in warmer months, creating challenges like carcass downgrades due to visible bite marks. Mosquito pressure may not always be treated as a major disease issue, but it can still create meaningful downstream economic loss.
• Operational pests: Fruit flies and Indian meal moths disrupt barns and feed systems, increasing labor demands and costs.
  
  

The goal isn’t just to identify pests; it’s to match the right response quickly. Use this framework to decide your next move.

• Flies present: focus on population control and sanitation
• Pigs irritated: treat for lice/mites
• Feed disruption: inspect for moths

 

Risk of different pests

Category	Key pests	Primary risk to herd
Disease vectors	House flies, roaches	Pathogen spread (animals + humans)
Performance pests	Lice, mange mites	Reduced gain, poor feed efficiency
Seasonal pests	Flies, mosquitoes	Peak pressure, carcass impacts
Operational pests	Fruit flies, Indian meal moths	Labor disruption, feed system issues

 

Seasonality vs. constant risk

Flies and mosquitoes thrive in warmer months, with populations often increasing rapidly and catching operations off guard. These are the pests producers are most likely to feel acutely in summer—but that seasonal visibility can create a false sense that all pest pressure is seasonal.

 

Lice and mites persist throughout the year, particularly in modern barns with stable environmental conditions. As Morris explains, “Within the confines of the barns they’re kind of there year-round.” Because swine barns are managed to stay relatively stable, internal pest pressure does not always follow the same seasonal pattern as outdoor pests.

By the time pests are visible, populations are already established. That is why the most effective pest management programs are preventive, not reactive. Producers who wait until they see the first fly may already be behind the problem.

 

Seasonality snapshot

Pest Type	Seasonality
Flies	Peak summer
Mosquitoes	Peak summer
Lice	Year-round
Mites	Year-round
Feed pests	Variable, often year-round indoors

 

What this means in practice:

• If temperatures are rising: start fly and mosquito prevention now
• Regardless of season: assume lice and mites are present indoors
  
  

From nuisance to risk: The health consequences of pests

Pests like flies act as vectors for diseases such as Porcine Reproductive and Respiratory Syndrome (PRRS), which contributes to significant mortality in the United States swine population. Just as importantly, pests do not create these diseases—they help spread them. That makes pest management part of a broader prevention strategy, not a separate maintenance issue.

Even without disease, pest pressure creates chronic stress and irritation, leaving animals more vulnerable to illness and reducing their ability to perform at their genetic potential. For producers, that means pest control supports both disease prevention and day-to-day performance.

Evolving pest management strategies

Modern approaches focus on precision. Innovative products like natural insecticides made from chrysanthemum offer effective, easy-to-apply solutions that are safe for animals and workers. Battery-powered sprayers further simplify application.

• Likely parasite pressure (lice or mites) disrupting feeding behavior

We offer operation-specific solutions, including natural insecticides, feed-through products, and traditional options when effective. That matters because no two farms face the same pest profile, resistance pattern, or operational constraints.

Rather than applying a broad solution and hoping for improvement, producers can take a more targeted approach, one built around the actual pests present on their farm and the products most likely to work.

When to use each solution

• Feed-through products → control flies at the source
• Contact insecticides/sprays → reduce active pest pressure quickly
• Rotation strategies → prevent reduced efficacy over time