Mastitis is one of the most common and costly health issues in dairy herds. Because of this, early detection is important. A strong mastitis screening program can alert you to problems before they spread. As a result, you can protect milk quality, reduce losses, and improve herd health.
Why Mastitis Screening Matters
Mastitis caused by contagious bacteria can move quickly through a herd. Environmental mastitis can spread just as fast. When these infections go unnoticed, farms can face losses such as:
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Higher somatic cell counts
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Lower milk production
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Treatment and veterinary costs
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Removed or culled animals
However, regular screening helps catch infections early. This gives you time to act before the issue becomes larger and more expensive.
What Increases Your Herd’s Risk?
Some farms carry more risk than others. For example, risk increases when:
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Purchased cows enter the herd without testing
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Young stock and adult cows share airspace
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Animals mix with cattle from other herds
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Clinical mastitis cases are not treated
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Dry cow therapy is not used
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Teat dip is not effective
In addition, herd stress and immunity also influence how quickly cows become infected.
Understanding these risks helps you decide how often to screen.
Types of Mastitis Screening Tests
1. Bulk Tank Somatic Cell Count (BTSCC)
BTSCC gives a big-picture view of udder health. When the count climbs, it often means something has changed.
However, in large herds, BTSCC rises slowly. This delay may give infections more time to spread.
Best use:
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Routine monitoring
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Early signal that individual cows need testing
2. Bulk Tank Culture
Bulk tank cultures look for bacteria in the tank sample. They can detect important pathogens such as Mycoplasma spp., Strep agalactiae, and Staph aureus.
However, a single test may miss low-level infections. Therefore, repeated sampling over several days increases accuracy.
Best use:
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Finding contagious pathogens
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Supporting BTSCC trends
3. Individual Cow Culture
Individual cow testing is more targeted. It also provides clearer information.
Full mastitis cultures:
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Identify the exact organism
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Guide treatment
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Help with culling and herd decisions
Screening cultures:
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Lower cost
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Confirm whether a contagious pathogen is present
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Often used on fresh cows and high-SCC cows
Best use:
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Pinpointing infected cows early
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Designing a focused prevention plan
4. PCR Testing
PCR detects bacterial DNA. It is extremely fast and highly sensitive.
This method is especially useful for detecting Mycoplasma spp., which grows slowly on culture plates. PCR delivers results in hours rather than days.
In addition, on-farm PCR kits are becoming available, offering quick answers without shipping samples.
Best use:
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Rapid detection of contagious mastitis
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High-risk or fast-moving herd situations
Choosing the Right Screening Program
Every herd is different. Therefore, your screening program should fit your herd size, risk level, and goals.
More Aggressive Programs May Include:
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Routine bulk tank testing
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Culture or PCR tests on:
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Fresh cows
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High-SCC cows
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Cows with clinical mastitis
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Moderate Programs May Include:
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Monthly or quarterly bulk tank cultures
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Screening cultures on selected individuals
Although these plans vary, both can reduce the spread of mastitis and protect milk quality.
The Bottom Line
Mastitis screening is a simple way to stay ahead of udder health issues. It:
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Finds infections earlier
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Reduces treatment and culling costs
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Protects milk production
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Strengthens herd health over time
With the right program in place, mastitis is easier to manage and far less likely to become a costly crisis.
