Somatic cell count measures the number of somatic cells in each milliliter of milk. This figure acts as a core indicator of milk quality and udder health. Dairy farmers rely on somatic cell count tester for accurate herd monitoring and early detection of problems. High somatic cell count usually signals infection, which can lower milk quality. Monitoring helps protect both herd health and the interests of consumers.
Key Takeaways
- Somatic cell count (SCC) measures the number of cells in milk and shows udder health and milk quality.
- High SCC often signals infection like mastitis, which lowers milk quality and reduces milk production.
- Regular SCC testing helps farmers detect infections early and protect herd health and milk value.
- Keeping SCC low improves milk taste, shelf life, and farm profits by avoiding losses and penalties.
- Using modern SCC testers and good farm practices supports sustainable and successful dairy farming.
Somatic Cell Count Basics
What Are Somatic Cells?
Somatic cells are natural components found in milk. These cells mainly include lymphocytes, polymorphonuclear neutrophils (PMN), and macrophages. In a healthy udder, macrophages and lymphocytes dominate, which shows the immune system is working normally. When infection occurs, PMN levels rise quickly to fight off bacteria. If PMN levels stay high and the somatic cell count remains elevated, this often means the cow has an ongoing infection or chronic mastitis. By monitoring the types and proportions of somatic cells, farmers can better understand udder health and take action before problems worsen.
Somatic cell count, often called SCC, measures the number of somatic cells in each milliliter of milk. This number acts as a key indicator of udder health and milk quality. A low SCC usually means the cow is healthy, while high somatic cell count in milk can signal infection or inflammation. Farmers and milk processors use SCC as a standard for monitoring herd health and ensuring high milk quality.
SCC Measurement
Farmers and laboratories use several methods to measure somatic cell count in milk. The most common approach is microscopic counting, which remains the regulatory standard. This method involves preparing a milk sample, staining it, and counting the somatic cells under a microscope. Although accurate, this process can be time-consuming and requires skilled personnel.
Other methods include fluorescence photoelectric counting, Coulter counting, and flow cytometry. These direct detection methods offer rapid and efficient results but often require expensive equipment and trained staff. Indirect methods, such as the California Mastitis Test (CMT) and ATP bioluminescence detection, provide quick screening but may lack accuracy. Many dairy farms now use a somatic cell count tester for routine monitoring, which helps detect problems early and maintain milk quality.
Tip: Regular monitoring with a somatic cell count tester helps farmers catch udder infections before they affect bulk milk quality or herd health.
Below is a table summarizing the main SCC measurement methods:
| Method Category | Specific Methods | Applicability | Advantages | Disadvantages |
|---|---|---|---|---|
| Traditional Method | Microscopic Counting | Regulatory standard | Direct enumeration, established procedure | Complex, time-consuming, visual fatigue |
| Direct Detection Methods | Fluorescence Photoelectric Counting | Enumeration method | Rapid, efficient, high reproducibility | Expensive equipment, specialized personnel |
| Coulter Counting | Enumeration method | Rapid detection | Complex pretreatment, bacterial interference | |
| Flow Cytometry | Enumeration method | Straightforward, efficient | High cost | |
| Indirect Detection Methods | California Mastitis Test (CMT) | Screening method | Low cost, easy to operate | Only qualitative, subjective evaluation |
| ATP Bioluminescence Detection | Screening method | Simple, rapid detection | Low accuracy, bacterial interference | |
| Conductivity and pH Detection | Screening method | Simple detection process | Lacks accuracy, needs microscopy for confirmation |
Healthy cows usually have an SCC below 200,000 cells per milliliter. This level indicates good udder health and high milk quality. When SCC rises above 200,000 cells/mL, it often marks the mastitis somatic cell count. Bulk milk from herds with high somatic cell count can lead to lower milk quality and reduced shelf life. Legal limits for SCC in bulk milk vary by country. For example, the European Union, China, New Zealand, Australia, Switzerland, and Canada set the legal limit at 300,000 to 400,000 cells/mL. In the United States, the legal limit for bulk milk is 750,000 cells/mL.
The following table shows healthy SCC ranges and legal limits in major dairy markets:
| Condition / Milk Type | Somatic Cell Count (cells/mL) |
|---|---|
| Healthy cows | Below approximately 2.0×10^5 |
| Pregnant cows | Around 2.0×10^5 |
| Colostrum (day of calving) | Around 4.0×10^5 |
| Subclinical Mastitis (SCM) | Around 4.6×10^5 |
| Clinical Mastitis (CM) | Up to 7.5×10^5 |
| Country / Region | Legal Bulk Milk SCC Limit (cells/mL) |
|---|---|
| European Union, China, New Zealand, Australia, Switzerland, Canada | 3-4×10^5 |
| South Africa, Brazil | 5×10^5 |
| United States of America | 7.5×10^5 |
Farmers use the somatic cell count score to track changes in SCC over time. SCS provides a way to compare SCC results and monitor trends in bulk milk. Regular monitoring helps farmers keep SCC within healthy ranges, protect milk quality, and avoid penalties for exceeding legal limits.
Why It Matters?
Detecting Mastitis
High somatic cell counts serve as a warning sign for udder infections, especially mastitis. Mastitis remains the most common cause of increased SCC in dairy cows. When cows become infected, their immune systems send more white blood cells to the udder, raising the SCC in milk. Dairy farmers often rely on a somatic cell count tester to spot these changes early.
- Elevated SCC above 200,000 cells/mL in the first month of lactation signals subclinical mastitis.
- Cows with subclinical mastitis show persistently high SCC linear scores throughout lactation.
- Multiparous cows experience a stronger effect from subclinical mastitis than first-lactation cows.
- Cows infected with subclinical mastitis and high SCC produce less milk and face a higher risk of culling.
- High SCC reflects ongoing infection and inflammation, making it a key marker for early detection.
Other factors can also raise SCC, such as stage of lactation, parity, stress, and nutrition. Poor milking hygiene and improper machine settings increase the risk of mastitis. Supplementing cow diets with vitamins and trace minerals like zinc and selenium supports immune health and helps maintain low somatic cell levels.
Note: Early detection of mastitis using a somatic cell count test kit allows dairy farmers to treat cows before infections become severe, protecting both milk quality and herd health.
Impact on Milk Quality
High somatic cell counts have a direct and negative effect on milk quality. When SCC rises, the composition of milk changes, and its value drops. The table below shows how high SCC alters milk components and sensory properties:
| Milk Component / Quality Attribute | Effect of High Somatic Cell Count (SCC) |
|---|---|
| Leukocytes and immune cells | Increase (response to infection) |
| Enzymes (lipases, proteases) | Increase (degrade fat and protein) |
| Milkfat | Decrease (due to lipase activity) |
| Protein (casein) | Decrease (due to protease activity) |
| Whey protein | Increase |
| Lactoferrin | Increase |
| Lactose | Decrease |
| Potassium | Decrease |
| Sodium | Increase |
| Chloride | Increase |
| Sensory attributes (flavor, odor) | Negative impact; off-flavors such as rancidity, saltiness, bitterness |
| Coagulation time | Longer (affects cheese-making) |
| Milk quality overall | Reduced quality, shorter shelf life, financial losses |
High SCC milk contains more enzymes that break down fat and protein, leading to lower milkfat and casein levels. These changes reduce the nutritional value and processing quality of milk. Cheese makers notice longer coagulation times and lower cheese yields. High SCC also causes off-flavors, such as bitterness or saltiness, which make the milk less appealing to consumers. As a result, processors may reject high SCC milk, and shelf life decreases.
Maintaining low somatic cell levels ensures better milk quality, higher cheese yields, and improved taste. Regular use of a somatic cell count tester helps dairy farmers monitor and control somatic cell count score, protecting the value of their milk.
Effects on Farm Profitability
High somatic cell counts do not only affect milk quality; they also impact farm profitability. When SCC stays high, milk production drops, and economic losses rise. Studies show that farms with high SCC, especially above 500,000 cells/mL, lose both milk quantity and quality. Over three months, these losses can average $557 per farm. Chronic high SCC leads to daily milk yield losses, which increase over time. For example, a cow may lose $1.20 per day in the first month of high SCC, rising to $2.06 per day by the tenth month.
High SCC milk often requires withdrawal from the market during treatment, reducing income. Treating affected cows proves more cost-effective than culling, with an expected gain of $1,186 over three years if treatment succeeds. However, cows infected with chronic mastitis and high SCC face a higher risk of being culled, which increases replacement costs for the farm.
Other factors, such as poor milking practices, stress, and nutritional imbalances, can raise SCC and further reduce profitability. Proper management, regular use of a somatic cell count tester, and good nutrition help dairy farmers keep SCC low, protect milk production, and maintain a healthy herd.
Tip: Investing in prevention and early detection of high SCC saves money and supports long-term farm success.
Somatic Cell Testing
Testing Methods
Dairy farmers use a range of methods for somatic cell testing to ensure milk quality and udder health. The most common approaches include:
- Laboratory-based systems such as Fossomatic, Coulter counters, and Bentley Somacount. These provide accurate and rapid scc measurement but require specialized equipment and trained staff.
- Rapid on-farm or “cow-side” tests like the California Mastitis Test (CMT), Wisconsin Mastitis Test (WMT), and Whiteside test. Farmers prefer these for their simplicity and speed when testing milk directly from cows.
- Biosensor-based methods are emerging as a trend, offering low cost, fast detection, and high sensitivity for on-site use.
- Monthly laboratory scc testing remains a standard practice for herd monitoring.
Large-scale operations often rely on centralized, instrument-heavy testing, while small-scale farms benefit from portable, user-friendly devices. Recent advancements include smartphone-based point-of-care tool and somatic cell counter for milk, which deliver results in minutes and help farmers monitor scc in real time. New technologies also feature artificial intelligence, cloud connectivity, and integration with farm management software, making somatic cell testing more efficient and accessible.
Interpreting Results
Farmers must interpret somatic cell testing results carefully to identify udder health issues. The process usually follows these steps:
- Collect and culture milk samples, including bulk tank somatic cell count and individual cow scc samples, to find the cause of high scc.
- Analyze the culture to distinguish between environmental and contagious bacteria.
- Use individual cow scc data from DHIA or CMT paddle tests to pinpoint cows contributing to high scc.
- Develop a management plan based on the bacteria type. For contagious bacteria, farmers may milk infected cows last, sanitize equipment, or consider culling. For environmental bacteria, they improve bedding, milking routines, and equipment maintenance.
- Maintain consistent milking routines and equipment checks to keep scc low.
Tip: Accurate interpretation of somatic cell testing results helps farmers take targeted action and maintain herd health.
Taking Action
After interpreting results, farmers act to reduce scc and prevent future problems. They may treat infected cows, improve hygiene, and adjust milking procedures. Regular monitoring with a somatic cell count tester or other milk testing tool helps detect issues early. Preventive steps include:
- Keeping bedding clean and dry
- Following strict milking routines
- Maintaining equipment
- Supporting cow immunity with proper nutrition
Somatic cell testing supports compliance with regulatory standards in major dairy markets. By using modern testing and monitoring tools, farmers protect milk quality and profitability.
Conclusion
Regular SCC monitoring gives dairy farmers a powerful tool for protecting herd health and milk quality. Using a somatic cell count tester helps identify cows with high SCC, allowing for targeted management.
- Early dry-off or culling of affected cows reduces mastitis and improves overall herd health.
- SCC monitoring supports better milk quality and profitability.
Good management and routine testing keep SCC low. Dairy farms that prioritize SCC management build a foundation for sustainable and successful operations.
FAQ
What Is a Normal Somatic Cell Count In Milk?
Healthy cows usually have a somatic cell count below 200,000 cells per milliliter. Farmers use a somatic cell count tester to check if milk meets this standard. Lower counts mean better udder health and higher milk quality.
How Often Should Farmers Test for Somatic Cell Count?
Most dairy farms test monthly. Some use a somatic cell count tester weekly for early detection of problems. Frequent testing helps farmers catch infections quickly and maintain milk quality.
Can High Somatic Cell Count Affect Milk Safety?
Yes. High somatic cell count often signals infection, which can lower milk safety. Processors may reject milk with high counts. Using a somatic cell count tester helps farmers ensure milk stays within safe limits.
What Tools Help Farmers Monitor Somatic Cell Count?
Farmers use several tools:
- Somatic cell count tester
- Laboratory analysis
- On-farm rapid tests
Regular use of these tools helps farmers maintain healthy herds and high-quality milk.