Dairy farms often face a choice between a somatic cell counter for milk and traditional lab tests. The somatic cell counter for milk offers speed and convenience, making it ideal for rapid on-farm decisions. Traditional lab methods, on the other hand, provide high accuracy and consistency. Somatic cell count plays a critical role in milk quality, as elevated values often signal udder health problems and bacterial contamination. Different testing methods help maintain dairy quality and safety. A recent study compared several methods, showing unique strengths for each:
Testing Method
Agreement with FSCC (%)
Sensitivity (%)
Specificity (%)
Correlation with FSCC
Agreement with Microbiological Culture (%)
California Mastitis Test (CMT)
83.1
81.0
92.9
N/A
69.2
Porta Somatic Cell Count (Porta SCC)
80.6
79.4
90.7
0.86 (p < 0.0001)
73.7
DeLaval Cell Counter (DCC)
80.3
75.8
97.5
0.92 (p < 0.0001)
71.6
Fossomatic FC (FSCC) (Gold Standard)
N/A
N/A
N/A
N/A
76.5
These methods support both routine milk quality monitoring and quick detection of udder issues. Choosing the right test ensures healthy dairy herds and premium milk.
Key Takeaways
Somatic cell count is a vital indicator of milk quality and udder health, with high somatic cell count signaling mastitis and reduced milk production.
Somatic cell counter provides fast, easy, and on-farm testing, enabling early detection and better herd management.
Traditional lab test offers the highest accuracy and consistency, essential for regulatory compliance and detailed milk analysis.
Choosing the right test depends on farm size, budget, testing frequency, and the need for speed versus precision.
Combining on-farm testing with lab analysis helps maintain milk quality, prevent losses, and support healthy dairy herds.
Somatic Cell Count in Milk
Why Somatic Cell Count Matters?
Somatic cell count serves as a key milk quality indicator for dairy farms. This count reflects the number of white blood cells and epithelial cells present in milk samples. High somatic cell counts often signal subclinical or clinical mastitis, which can harm both udder health and milk production. Dairy producers use somatic cell count score to detect early signs of mammary gland infection, even before visible symptoms appear. A threshold of 200,000 cells/ml typically identifies subclinical mastitis, while higher levels suggest clinical cases.
Recent studies show that every 100,000 cells/ml increase above 200,000 leads to a 2.5% drop in daily milk production. Over a standard lactation period, this reduction can exceed 363 kg per cow. Factors such as parity, lactation stage, season, and management practices influence cell counts. Multiparous cows and those in late lactation often show higher counts due to increased infection risk. Dairy farms that implement mastitis control programs and use somatic cell count test kit see improvements in both udder health and milk quality control.
Differential somatic cell count at the quarter level helps veterinarians and producers better understand infection dynamics and tailor mastitis management strategies.
Impact on Milk Quality
Somatic cell count directly affects milk quality and marketability. High cell counts change the composition of milk, reducing fat, lactose, casein, and protein levels. Enzymes released by immune cells, such as lipases and proteases, degrade milkfat and protein, leading to off-flavors like rancidity, bitterness, and a salty taste. These changes lower the quality of dairy products and can cause processors to reject milk or impose penalties.
Decreased milk yield and lower cheese quality due to casein breakdown.
Poorer coagulation properties, affecting cheese-making and shelf life.
Increased sodium and chloride, altering taste and processing performance.
Reduced market value and higher risk of financial loss for dairy farms.
Low somatic cell count supports better milk quality assessment, consistent product quality, and higher economic returns. Regulatory standards for somatic cell count vary by country, affecting milk quality control and market access.
Maintaining low cell counts through regular testing, including the use of somatic cell count tester, helps dairy farms meet quality standards and ensures safe, high-quality milk for consumers.
Test Methods Overview
Somatic Cell Counter for Milk
A somatic cell counter for milk uses advanced technology to deliver rapid and accurate test results. Devices like the ADAM-SCC2 stain milk samples with a fluorescent dye that binds to DNA in somatic cell nuclei. The sample is then placed on a chip, and the device captures multiple images for analysis. Automated image analysis software counts the cells, providing results in less than 13 seconds per test. This method does not require calibration and offers easy operation, making it suitable for dairy farms, research, and veterinary clinics.
Stained cells arranged in single file, passed through laser beam
Results
Fast (seconds), reliable, reproducible
Application Scope
Dairy management, mastitis detection, milk quality control
Recent advancements include portable and benchtop devices with automation, cloud connectivity, and integration with dairy management software. Some models, such as the porta somatic cell count milk test, offer low-cost, on-site testing. These methods help dairy producers monitor milk quality and detect udder health issues quickly. The somatic cell count tester supports early intervention and better herd management.
Traditional Lab Test
Traditional lab tests for somatic cell count began with manual microscopic examination of milk samples. Technicians counted cells under a microscope, which required skill and time. In the 1970s, automated flow cytometry improved accuracy and speed, becoming the gold standard for somatic cell count testing. Modern labs now use imaging-based systems that deliver reliable results without specialized operators.
Common methods include:
Direct microscopic somatic cell count (DMSCC)
Automated flow cytometry
Imaging-based counters
Lab-based methods provide high accuracy and consistency for milk testing. However, these tests can face errors, such as difficulty distinguishing somatic cells from non-cellular particles, especially in goat and sheep milk. Color artifacts, cell aggregation, and limited sample volume can also affect results. Despite these challenges, lab tests remain essential for regulatory compliance and detailed milk quality analysis.
Accuracy and Reliability
Automated Counter Performance
Somatic cell counter has transformed on-farm testing by providing rapid results for milk quality monitoring and mastitis detection. The device uses advanced methods such as fluorescence optics, image analysis, or viscosity-based techniques to estimate somatic cell count in milk. The accuracy of these counters varies depending on the method and the range of cell counts present.
Recent comparative studies show that online somatic cell counters, like the O-CMT, achieve moderate agreement with laboratory flow cytometry, especially when cell counts exceed 500,000 cells/mL. However, their accuracy drops in the low somatic cell count range, which is critical for early subclinical mastitis detection. The overall concordance correlation coefficient for these counters hovers around 0.53, indicating moderate reliability. Averaging multiple measurements over a 24-hour period can improve agreement with laboratory results, making these devices useful for monitoring trends rather than providing single definitive results.
Aspect
Online Somatic Cell Counter (O-CMT)
Traditional Laboratory SCC (L-SCC)
Measurement Technique
Viscosity-based CMT-derived method
Flow cytometry (gold standard)
Overall Concordance Correlation Coefficient (CCC) with L-SCC
Moderate, ~0.53
N/A (reference standard)
Accuracy in Low SCC Range (<200,000 cells/mL)
Lower accuracy
High accuracy
Accuracy in High SCC Range (>500,000 cells/mL)
Improved, fair to good correlation
High accuracy
Calibration and Quality Control
Factory calibrated, variable compliance
Rigorous calibration, ISO certified
Effect of Averaging Multiple Measurements
Improves correlation
Not applicable
Practical Use
Frequent on-farm measurements
Less frequent, more costly
Repeatability is another important factor for automated counters. Field studies using automatic milking systems report an intraclass correlation coefficient of 0.58, which suggests moderate repeatability. This means that while automated counters can reliably track changes in cell counts over time, some variation may occur due to biological factors or measurement error. The use of preservatives like bronopol in milk samples can enhance repeatability, as shown in studies with ovine milk, where standard deviations ranged from 16.3 to 19.7 and relative repeatability percentages stayed between 1.9% and 2.4%. Analytical temperature had minimal impact on the variation of somatic cell counts.
Proper calibration and species-specific adjustments are essential for reliable results. For example, somatic cell count tester calibrated with cow milk standards may overestimate cell counts in goat milk by about 24%. When calibrated specifically for goat milk, automated counters closely match microscopic counting results. This highlights the importance of using the correct calibration and handling protocols for each type of milk.
Note: Somatic cell counter offers fast, practical testing for mastitis and milk quality, but the accuracy depends on proper calibration, sample handling, and user training.
Lab Test Consistency
Traditional laboratory methods remain the gold standard for somatic cell count in milk. These methods, including flow cytometry and direct microscopic counting, provide high accuracy and reliability, especially for regulatory and quality control purposes. Laboratories follow strict calibration protocols and participate in proficiency testing programs to ensure consistent results.
However, some challenges exist. The reference method, which relies on direct microscopic counting of stained cells, can be tedious and sometimes lacks precision. This can introduce variability and uncertainty in results between laboratories. Many labs use internal reference systems to address the lack of a universal standard. Efforts are underway to develop a worldwide harmonized reference system with primary reference materials. This system aims to anchor somatic cell count levels and calibrate routine methods globally, improving the equivalence and validity of results.
Recent studies comparing automated counters and laboratory methods highlight the strengths of lab-based testing. For example, flow cytometry-based counters like the Fossomatic 5000 demonstrate optimal repeatability and accuracy, especially when milk samples are preserved with bronopol. Repeatability percentages for these methods range from 1.9% to 2.4%, and preserved samples show no significant bias. Analytical temperature has little effect on the results, further supporting the reliability of these methods.
Somatic Cell Counter
Method Type
Preservation Used
Repeatability (s_r %)
Accuracy vs Reference
Notes
Fossomatic 360
Cytometry on disk
Bronopol
Slightly less repeatable
Adequate
Repeatability better at 40°C than 60°C
Fossomatic 5000
Flow cytometry
Bronopol
More repeatable (1.9-2.4%)
Closer to reference method
Optimal repeatability and accuracy; preserved samples showed no significant bias
User training and experience also impact laboratory test accuracy. The FDA’s Milk Proficiency Testing Program requires annual proficiency tests for certified analysts. Failure to meet standards leads to retraining or corrective actions. This structured approach ensures that analysts maintain high competency, which supports uniformity and accuracy in somatic cell count testing nationwide. When federal programs are unavailable, states and labs must independently uphold training and quality assurance, highlighting the ongoing need for skilled personnel.
Laboratory methods excel in detecting both subclinical and clinical mastitis, providing reliable results for milk quality assessment and regulatory compliance. These methods support detailed analysis of milk samples, making them essential for dairy processors, veterinarians, and researchers who require precise data.
Tip: For the most accurate and reliable somatic cell count results, laboratories should use properly calibrated equipment, preserve milk samples with recommended agents, and ensure analysts receive regular training.
Speed and Convenience
Test Time Comparison
Speed plays a crucial role in milk testing on dairy farms. Somatic cell count tester delivers results in seconds. For example, many portable counters can complete a test in less than 15 seconds per milk sample. This rapid turnaround allows farmers to make immediate decisions about milk quality and udder health. On-farm methods such as the California Mastitis Test also provide quick results, though they offer only semi-quantitative data.
Traditional laboratory methods require more time. Samples must be collected, preserved, and transported to a lab. Once there, technicians use flow cytometry or direct microscopic analysis. These tests often take several hours to process, especially when labs handle large batches. Delays can occur if the lab is far from the farm or if there is a backlog of samples. As a result, lab-based testing is less suitable for urgent situations where fast action is needed.
Quick on-farm testing helps farmers detect mastitis early and maintain milk quality, while lab methods remain best for detailed analysis.
Ease of Use
Ease of use sets somatic cell count tester apart from traditional lab methods. On-farm counters such as the Porta SCC and DeLaval Cell Counter are accurate and user-friendly. Farmers can operate these devices with minimal training. The process involves adding a reagent to the milk, inserting the sample, and reading the result. Portable systems like the C-reader use disposable microchips and microfluidic technology, making daily testing simple and reducing the need for complex equipment.
In contrast, traditional lab testing methods require specialized equipment and trained staff. Direct microscopic analysis demands skill to ensure accurate results. Flow cytometry-based counters, such as the Fossomatic, need regular calibration and maintenance. Farmers must also transport milk samples to the lab, which adds extra steps and potential for error.
On-farm somatic cell count tester devices:
Provide fast, practical testing for routine milk quality checks.
Allow frequent monitoring without waiting for lab results.
Reduce the need for technical expertise.
Lab-based methods:
Offer high accuracy but require more resources and time.
Remain essential for regulatory and research purposes.
Farmers benefit from the convenience and accessibility of on-farm testing, especially when managing herd health and milk quality on a daily basis.
Cost Factors
Device and Test Costs
Dairy farms and laboratories face different initial costs when choosing between a somatic cell count tester and traditional lab tests. Automated counters often require a significant upfront investment. Prices for portable or benchtop devices can range from $2,000 to $10,000, depending on features and brand. Some models, like the ADAM-SCC2, include advanced imaging and cloud connectivity, which can increase the price.
Traditional lab testing does not require farms to purchase equipment. Instead, they pay per test, usually between $1 and $3 for each milk sample. This cost covers technician labor, reagents, and equipment maintenance at the lab. For large dairy operations, frequent testing can add up quickly.
Option
Upfront Cost
Per-Test Cost
Who Pays?
Somatic cell count tester
High
Low
Farm/Lab
Traditional lab test
Low
Moderate
Farm (per sample)
Tip: Farms with high milk production may save money over time by investing in their own somatic cell count tester.
Ongoing Expenses
Ongoing expenses also differ between the two methods. Automated counters need regular supplies, such as reagents, chips, or cartridges. These consumables usually cost $0.50 to $1 per test. Maintenance and occasional calibration add to the total expense, but these costs remain predictable.
Traditional lab testing involves recurring sample shipping fees and possible delays. Farms may experience indirect losses if slow results lead to undetected mastitis, which can reduce milk production and quality. These losses can impact overall dairy profitability.
Dairy producers must consider both direct and indirect costs. Quick detection of udder health issues with a somatic cell count tester can help prevent production losses and maintain high-quality milk. In contrast, relying solely on lab tests may increase the risk of undetected problems and greater financial losses.
Early detection and frequent monitoring help dairy farms reduce milk production losses and protect their bottom line.
Practical Applications
On-Farm Testing
On-farm testing has become a vital part of modern dairy management. Farmers now use automated devices like the somatic cell counter for milk to monitor udder health and milk quality directly on the farm. These devices allow quick testing of milk samples, giving results in seconds. Farmers can identify mastitis early, even before clinical signs appear. This early detection helps prevent the spread of infection and reduces milk losses.
A Scottish sheep farm demonstrated the value of on-farm somatic cell count testing. Over a ten-week period after lambing, the farm used repeated sampling and somatic cell counters to diagnose subclinical mastitis in ewes. By combining cell counts with bacterial cultures, the farm set clear thresholds for infection. This approach improved both udder health and milk quality.
Dairy farms also benefit from systems like the QualiTru inline sampling system. This technology integrates with milking equipment to monitor somatic cell count in real time. Farmers receive immediate alerts when cell counts rise, allowing them to act quickly. These systems support regular milk quality control and help maintain profitability.
Somatic cell counter offers several advantages for on-farm testing:
Reduced veterinary costs and improved animal welfare
Support for compliance with milk hygiene standards
Farmers can use these tools to test individual cows or groups, track trends, and make informed decisions. Frequent testing with a somatic cell count tester helps maintain high milk quality and reduces the risk of financial loss.
Lab-Based Analysis
Veterinarians and dairy labs rely on traditional lab tests to provide detailed analysis of milk samples. These tests include somatic cell count measurement and the California Mastitis Test. Labs use these methods to diagnose both subclinical and clinical mastitis, assess milk quality, and guide treatment decisions.
Veterinarians often use somatic cell count and the California Mastitis Test as part of routine herd health checks. These tests are simple and require minimal training. They help screen for intramammary infections and monitor milk quality. Sensitivity and specificity for these tests remain high, making them reliable tools for mastitis management.
In dairy labs, somatic cell count serves as the gold standard for detecting subclinical mastitis. Labs use a threshold of 200,000 cells/mL to separate healthy cows from those with infections. The California Mastitis Test provides a quick, indirect estimate of cell counts by observing gel formation in milk samples. Results from these tests influence milk pricing and quality control decisions.
Lab-based analysis offers several benefits:
High accuracy and repeatability of results
Detailed data for regulatory compliance
Support for research and herd health programs
Reliable detection of both subclinical and clinical mastitis
Veterinarians and labs use these results to recommend treatment, improve milking routines, and advise on hygiene practices. Proper use of lab tests helps dairy farms maintain milk quality and meet industry standards.
Note: Both on-farm testing and lab-based analysis play important roles in mastitis detection and milk quality control. Automated somatic cell counters provide rapid, actionable results for daily management, while lab tests deliver detailed data for long-term herd health and regulatory needs.
Limitations
Counter Limitations
Somatic cell count tester has improved the speed and convenience of mastitis detection, but the tester still face technical challenges. Different methods, such as microscopic counting, fluorescence photoelectric detection, and flow cytometry, each come with their own drawbacks. The table below outlines the main technical limitations for common somatic cell count methods used in milk testing:
Method Type
Method Name
Main Technical Limitations
Microscopic Methods
Microscopic counting
Complex to perform; prone to detection bias due to visual fatigue
Direct Detection
Fluorescence photoelectric
High cost; requires specialized operators; needs regular calibration
Direct Detection
Coulter counting
Interference from bacterial cells; complex pretreatment; does not specifically identify somatic cell DNA
Direct Detection
Flow cytometry
High cost; requires specialized operators
Indirect Detection
California Mastitis Test (CMT)
Provides only qualitative or relative results; influenced by subjective evaluation; cannot identify pathogens
Indirect Detection
ATP bioluminescence
Low detection accuracy; easily interfered by bacteria
Indirect Detection
Conductivity and pH detection
Lacks accuracy; requires microscopic confirmation for precise results
Somatic cell count tester may overestimate cell counts in goat milk or struggle with high cell counts due to interference from bacteria. Regular calibration and skilled operation remain necessary for accurate results. These limitations can affect the early detection of mastitis and the reliability of on-farm monitoring.
Lab Test Limitations
Traditional lab tests for somatic cell count in milk provide high accuracy, but they also present several practical challenges:
Lab tests are labor-intensive and require substantial sample pretreatment.
Non-cellular particles, such as lipid vesicles, can interfere with cell counting and reduce accuracy.
Simple methods like microscopy or Coulter counting often misidentify lipid particles as somatic cells.
Flow cytometry, while more accurate, involves multiple manual steps, including fluorescent staining and centrifugation, which makes the process time-consuming.
These manual steps limit the speed and practicality of traditional testing, especially for rapid mastitis detection.
Extended intervals between tests and high workload can delay the identification of mastitis, increasing the risk of high cell counts in milk.
Lab-based methods remain essential for regulatory compliance, but their limitations highlight the need for faster, more practical solutions like the somatic cell count tester for routine mastitis monitoring.
Choosing the Right Test
Factors to Consider
Selecting the best approach for mastitis detection and milk quality assessment depends on several important factors. Dairy farms must weigh their unique needs before choosing between a somatic cell count tester and traditional lab tests.
Testing Frequency: Dairy farms that need frequent monitoring benefit from on-farm somatic cell counter. The device allows daily or weekly checks, which helps catch mastitis early and reduce production losses.
Speed of Results: Rapid results are crucial when quick action is needed. Somatic cell count tester provides immediate feedback, while lab tests may take days.
Sample Type: On-farm counter works well for testing milk from individual cows or even specific mammary glands. This targeted approach is not possible with monthly lab testing.
Cost and Budget: Farms with limited budgets may prefer somatic cell counter. The device offers low per-sample costs, sometimes less than $1, making frequent testing affordable.
Scale of Operation: Large dairy operations may use both methods. They can use somatic cell count tester for routine checks and send samples to labs for regulatory compliance.
Staff Skills: On-farm devices require minimal training. Lab tests need skilled technicians and more complex procedures.
Regulatory Needs: Some regulations require lab-based results. Dairy farms must ensure compliance by submitting samples to certified labs when needed.
Dairy producers should match their testing strategy to their herd size, management style, and milk quality goals.
Conclusion
Choosing between a somatic cell count tester and traditional lab tests depends on the farm’s needs. Rapid on-farm testing supports early mastitis detection, helping maintain milk quality and herd health. Lab tests deliver highly accurate results for regulatory or detailed analysis. Experts recommend regular SCC monitoring, aiming for results below 200,000 cells/ml to protect milk quality. Integrating both methods, along with strict hygiene and health checks, ensures the best outcomes for milk production and overall quality.
FAQ
What Is a Somatic Cell Count Tester?
A somatic cell count tester is a device that measures the number of somatic cells in milk. Farmers and veterinarians use it to check udder health and milk quality. The tester provides fast results, helping detect mastitis early.
How Often Should Dairy Farms Use a Somatic Cell Count Tester?
Many experts recommend using a somatic cell count tester at least once a week. Frequent testing helps farmers spot problems early and maintain high milk quality. Large farms may test daily for better herd management.
Are Somatic Cell Count Testers Accurate for All Types of Milk?
Most somatic cell count testers work best with cow milk. Some devices may overestimate counts in goat or sheep milk. Proper calibration and using the right settings improve accuracy for different milk types.
Can a Somatic Cell Count Tester Replace Lab Tests?
A somatic cell count tester offers quick, on-farm results. However, lab tests remain important for regulatory compliance and detailed analysis. Many farms use both methods for the best results.
What Maintenance Does a Somatic Cell Count Tester Require?
Regular cleaning and calibration keep a somatic cell count tester accurate. Users should follow the manufacturer’s instructions. Some models need new reagents or chips after each test.
