The normal somatic cell count in cows plays a critical role in maintaining udder health status for dairy cows. Many dairy farms target an average somatic cell count below 200,000 cells/mL, which helps preserve milk quality and supports healthy udders. Elevated levels often signal issues with udder health or early signs of mastitis in dairy cows. Regular monitoring with a somatic cell count tester allows farmers to track udder health status and quickly respond to changes. Studies show that a low somatic cell count in cows links to better udder health status and higher milk yield in dairy cows.
Regular testing of somatic cell count score allows early detection of udder infections like mastitis, preventing milk loss.
Low somatic cell count improves milk yield, flavor, shelf life, and increases farm income through better prices.
Using portable SCC testers and following good hygiene practices reduce infection risks and support udder health.
Combining SCC monitoring with proper milking routines and quick action keeps cows healthy and milk safe.
Somatic Cell Count Basics
What Are Somatic Cells?
Somatic cells are a natural part of milk from dairy cows. These cells include white blood cells and epithelial cells that originate from the udder tissue. The presence of milk somatic cells helps protect the udder from infections and maintain overall udder health. Each type of cell plays a unique role in the defense system of dairy cows.
Predominant in healthy milk; engulf bacteria and release chemoattractants to recruit PMNs.
Polymorphonuclear Neutrophils (PMNs)
Increase during infection; kill microorganisms via oxidative and non-oxidative mechanisms; release reactive oxygen species and enzymes.
Lymphocytes
Key role in specific immunity by recognizing antigens.
Epithelial Cells
Contribute enzymes and antimicrobial proteins that protect against infection and affect milk quality.
Milk somatic cells also release enzymes such as lysozyme, cathepsin G, and elastase. These enzymes help destroy bacteria and provide antimicrobial activity. The presence of these cells and their products in milk supports the health of dairy cows and influences milk quality.
SCC as a Milk Quality Indicator
Somatic cell count (SCC) serves as a key indicator of milk quality in dairy cows. High levels of milk somatic cells often signal inflammation or infection in the udder. Several factors affecting somatic cell count include udder hygiene, cow health, and milking practices. Monitoring SCC helps farmers detect mastitis early and maintain healthy herds.
High SCC indicates increased inflammation and a higher risk of mastitis in dairy cows.
Herds with SCC above 200,000 cells/mL face greater mastitis risk than those below this threshold.
Elevated SCC links to more frequent antibiotic treatments and a higher chance of antibiotic residues in milk.
Milk processors use SCC as a payment parameter, rewarding producers who maintain low SCC and high milk quality.
Effective mastitis control, reflected by lower SCC, ensures safer milk and better dairy production outcomes.
Regular monitoring of milk somatic cells allows for early intervention and supports the overall health and productivity of dairy cows. Understanding the factors affecting somatic cell count helps farmers make informed decisions to improve milk quality and udder health.
Normal Somatic Cell Count in Cows
SCC Thresholds and Values
The normal somatic cell count in cows serves as a benchmark for udder health and milk quality in dairy cows. Most healthy cows maintain a somatic cell count below 200,000 cells per milliliter. This value reflects a well-functioning immune system and minimal inflammation in the udder. When the count rises above this threshold, it often signals the presence of infection or inflammation, which can compromise both milk yield and quality.
Researchers have compared somatic cell counts in healthy cows and those with subclinical mastitis. The following table summarizes their findings:
Parameter
Healthy Quarters (Mean ± SD)
Quarters with Subclinical Mastitis (Mean ± SD)
Diagnostic Cut-off
Sensitivity (Se)
Specificity (Sp)
Somatic Cell Score (SCS)
1.4 ± 1.3
4.5 ± 2.4
3.0 (100,000 cells/mL)
0.73 (95% BCI: 0.70–0.77)
0.90 (95% BCI: 0.89–0.91)
Differential SCC (DSCC, %)
55.6% ± 15.2%
80.4% ± 6.4
70.0%
0.95 (0.93–0.96)
0.83 (0.81–0.85)
This table shows that healthy quarters have much lower somatic cell scores and percentages of differential SCC than those with subclinical mastitis. The diagnostic cut-off of 100,000 cells/mL helps identify cows at risk for udder infections. Regular monitoring of these values allows dairy farmers to detect early changes and take action before clinical symptoms appear.
The industry recognizes that the best herds achieve an average somatic cell count as low as 134,000 cells/mL. In contrast, herds with poor udder health may reach levels of 284,000 cells/mL or higher. These differences have a direct influence on milk production, farm income, and animal well-being.
What Low and High SCC Mean?
A low somatic cell count in cows brings many benefits to dairy farmers and milk processors. The effects of maintaining a low SCC include:
Higher milk prices, as processors pay premiums for low SCC milk.
Increased milk production, with the best herds producing up to 11 pounds more milk per cow per day.
Enhanced net farm income, with gains of $159 per cow due to lower SCC.
Better pregnancy rates and lower death losses among dairy cows.
Note: Regular monitoring of milk somatic cells helps farmers identify cows with high SCC and manage infections quickly. This practice avoids penalties and increases profitability.
The effects of somatic cell count extend beyond financial outcomes. Scientific studies confirm that high somatic cell count in dairy cows leads to reduced milk yield and lower protein and lactose content. These changes decrease milk quality and limit its use for premium dairy products.
High somatic cell count also signals poor udder health, often linked to subclinical or clinical mastitis. The effects of high SCC include:
Increased risk of infection and inflammation in the udder.
Reduced milk production and quality.
Higher likelihood of antibiotic residues in milk.
Greater susceptibility to heat stress, especially in summer.
More frequent health problems in multiparous cows.
Several factors influence somatic cell count in dairy cows. These include udder hygiene, infection control, and herd management practices. Farmers can reduce SCC by separating infected cows, using proper teat dipping, and maintaining clean environments. Regular milk culturing helps identify infection types and guides targeted interventions.
The influence of milk somatic cells on herd health and milk quality cannot be overstated. By keeping the normal somatic cell count in cows within recommended limits, dairy farmers protect both animal health and their bottom line. Monthly SCC monitoring remains a key strategy for sustaining high-quality milk production and ensuring the long-term success of dairy operations.
Udder Health Status and SCC
SCC and Mastitis Detection
Somatic cell count plays a vital role in monitoring udder health status in dairy cows. Farmers and veterinarians rely on SCC as a routine indicator for bovine mastitis and intra-mammary infections. When the udder faces infection, the number of immune cells in milk rises sharply. This increase signals the activation of the cow’s immune system and marks the early stages of clinical mastitis.
SCC reflects the total number of immune cells present in milk.
Differential somatic cell count (DSCC) measures the proportion of specific immune cells, such as polymorphonuclear leukocytes and lymphocytes.
In the early phase of mastitis, the proportion of polymorphonuclear leukocytes can reach up to 95%, showing a strong immune response.
Elevated SCC and DSCC values often appear before visible clinical symptoms, serving as early warning signs for udder health status.
Combining SCC and DSCC improves the accuracy of detecting intra-mammary infections compared to using SCC alone.
SCC typically peaks early in lactation, decreases after calving, and increases with parity and throughout the lactation period.
Advanced models that combine SCC, DSCC, and milk mid-infrared spectral data further enhance early prediction of bovine mastitis.
The diagnosis of mastitis depends on recognizing these changes in SCC and DSCC. Early detection allows farmers to intervene before clinical signs worsen, protecting udder health and reducing the effects of infection. The influence of SCC on udder health status makes it a cornerstone of modern dairy management.
Parameter
Mastitis-Free Lactations
Week Of Mastitis Event
Fold Increase (Mastitis Vs. No Mastitis)
Somatic Cell Score (SCS)
2.43
5.96
~11.6-fold increase
Daily Total Somatic Cell Score (DTSCS)
2.25
5.66
~10.6-fold increase
Milk Yield (Liters)
37.7
33.9 (0 wk), 31.6 (1 wk post)
Decreases with mastitis
This table demonstrates the effects of clinical mastitis on udder health status. SCC and total somatic cell output rise dramatically during mastitis events, while milk yield drops. The diagnosis of mastitis relies on these measurable changes, highlighting the influence of SCC on both udder health and milk production.
The chart above illustrates the effects of mastitis on somatic cell scores and milk yield. As SCC increases, milk yield declines, emphasizing the importance of monitoring udder health status for early diagnosis of mastitis and prevention of severe clinical outcomes.
SCC Impact on Milk Yield
The effects of somatic cell count extend beyond mastitis detection. SCC directly influences milk yield and feed efficiency in dairy cows. Scientific studies show that high SCC levels, especially above 200,000 cells/mL, lead to significant reductions in milk production and changes in milk composition.
Parameter
Effect Of High SCC (250,000 cells/mL) Vs Low SCC (50,000 cells/mL)
Milk yield
Decrease by 1.6 kg/day
Dry matter intake (DMI)
Decrease by 0.3 kg/day
Milk produced per kg DMI
Decrease by 0.04 kg
Energy-corrected milk (ECM)
Decrease by 0.03 kg per kg DMI
Feed efficiency (milk-based)
Reduced feed efficiency
High SCC levels cause inflammation and damage to mammary epithelial cells. These effects result in decreased lactose content, altered protein fractions, and variable fat content in milk. Increased vascular permeability and enzymatic proteolysis further influence milk chemistry. The effects of intra-mammary infections become more pronounced as SCC rises, making SCC a critical marker for udder health status and milk quality.
SCC Severity Level
Effect On Daily Milk Yield (kg decrease per 1 point LS-SCC)
First lactation
0.349 kg decrease
Second lactation
0.539 kg decrease
Third lactation
0.676 kg decrease
The influence of SCC severity varies by parity and milk production quartile. Cows in later lactations experience greater reductions in milk yield when SCC rises. The effects of intra-mammary infections and bovine mastitis become more severe with higher SCC, impacting both udder health status and farm profitability.
Farmers who monitor SCC closely can minimize the effects of clinical mastitis and intra-mammary infections. Early intervention preserves udder health, maintains milk yield, and improves overall herd performance. The diagnosis of mastitis and the management of udder health status depend on understanding the influence of SCC and its effects on milk production.
Tip: Regular SCC testing helps farmers detect intra-mammary infections early, reduce the effects of bovine mastitis, and maintain optimal udder health status.
Measuring SCC
SCC Testing Methods
Dairy farms use several methods to measure somatic cell count (SCC) in cow milk. Each method offers unique advantages and limitations. The direct microscopic somatic cell count remains the regulatory standard because of its accuracy, but it requires skilled personnel and can be time-consuming. Direct detection methods, such as fluorescence photoelectric counting, Coulter counting, and flow cytometry, provide rapid and reproducible results. These methods, however, often require expensive equipment and specialized training. Indirect methods, including the California Mastitis Test (CMT), ATP bioluminescence, and conductivity or pH detection, are simple and cost-effective but may lack precision.
A novel approach, the OPD-Cu2+ colorimetric assay, combines accuracy with user-friendliness and strong resistance to bacterial interference. Studies show that this method closely matches microscopic counting results and offers lower variability, making it a reliable choice for routine SCC monitoring.
Method Type
Method Name
Applicability
Advantages
Disadvantages
Direct Detection
Microscopic Counting
Regulatory standard
Accurate, primary standard method
Complex, prone to detection bias due to visual fatigue
Direct Detection
Fluorescence Photoelectric
Enumeration
Rapid, efficient, high reproducibility
Costly, requires specialized personnel and calibration
Only qualitative, subjective, bacterial interference
Indirect Detection
ATP Bioluminescence
Screening
Simple, rapid
Low accuracy, easily interfered by bacteria
Indirect Detection
Conductivity and pH
Screening
Simple detection process
Lacks accuracy, requires microscopic confirmation
Novel Method
OPD-Cu2+ Colorimetric Assay
Quantification
Cost-effective, user-friendly, accurate, strong resistance to bacterial interference
New method, validated with real samples
Using a Somatic Cell Count Tester
A somatic cell count tester is a portable device designed for rapid SCC measurement on dairy farms. These testers, such as the DeLaval Cell Counter (DCC) and Porta SCC Milk Test, allow farmers to check SCC levels directly at the point of milking. Portable testers show strong agreement with laboratory-based methods, with correlation coefficients ranging from 0.81 to 0.99. They provide quick results and help farmers make timely decisions about udder health.
Method Comparison
Agreement Range
Sensitivity Range
Specificity Range
Correlation Coefficient Range
California Mastitis Test (CMT) vs. Laboratory
Up to 97.5% (low SCC) to 61.4%-86.3% (high SCC)
75.9% to 91.1%
97.5% to 99.2%
High agreement
Porta SCC Milk Test vs. Laboratory
50.0% to 95.8%
69.8% to 91.1%
90.7% to 99.2%
0.81 to 0.87
DeLaval Cell Counter (DCC) vs. Laboratory
70.5% to 98.3%
75.8% to 86.4%
96.6% to 100%
0.81 to 0.99
Regular SCC monitoring is essential for maintaining udder health. Experts recommend sampling bulk tank milk every 15 days and averaging results over several weeks. Automatic milking systems (AMS) and online sensors now enable frequent SCC measurements, even at every milking. This frequent monitoring helps farmers detect udder health issues early and respond quickly, reducing the risk of mastitis and improving milk quality.
Tip: Frequent SCC testing with portable testers or AMS sensors supports early intervention and helps maintain optimal udder health in dairy herds.
Maintaining Udder Health
Hygiene Practices
Farmers who focus on hygiene practices see clear improvements in udder health status for dairy cows. Clean, dry bedding prevents bacteria from multiplying and encourages cows to rest in stalls. A thorough milking routine includes wiping each teat with a clean towel, pre-dipping teats for at least 30 seconds, forestripping milk, and post-dipping immediately after milking. Regular equipment checks and replacing damaged liners help maintain proper vacuum pressure and reduce infection risk. Managing heat stress with fresh water and ventilation supports cow comfort and lowers stress-related effects on udder health status.
A scientific study found that cows with very clean hygiene scores had lower somatic cell counts than those with poor hygiene, especially during wetter months. This result highlights the importance of cleanliness for maintaining udder health status and milk quality.
Farm staff should wear clean gloves, use one towel per cow, and wash towels at high temperatures. Training employees on correct milking procedures and mastitis identification further reduces new infections and supports udder health status.
Early Mastitis Detection
Early mastitis detection relies on monitoring somatic cell count data at both herd and individual cow levels. Farmers use bulk tank milk SCC to spot herd-level changes in udder health status. Individual cow testing through Dairy Herd Improvement programs provides more detailed information. Cow-side tests like the California Mastitis Test offer quick, inexpensive detection of inflammation. Electronic sensors in milking systems can identify changes in milk conductivity, signaling early effects of mastitis.
Machine learning models now predict subclinical mastitis up to seven days before symptoms appear, using SCC and milk composition data. These strategies allow farmers to target treatment or culling decisions, improving udder health status and milk quality.
SCC Monitoring Tips
Routine SCC monitoring forms the backbone of udder health status management for dairy cows. Farmers track SCC trends to identify cows at risk for udder infections, especially those with elevated counts above 199,000 cells/mL. First-lactation cows usually show flatter SCC trends, while older cows face higher risks. Simple assessments like teat-end scoring and hygiene scoring guide preventive strategies.
Regular SCC checks help control herd SCC levels and support long-term udder health status.
Automated milking systems and frequent test-day data collection enable timely detection and intervention.
Proper milking techniques, equipment maintenance, and pre- and post-milking teat disinfection reduce the effects of poor udder health status.
Tip: Farmers who maintain low SCC through routine checks and targeted management strategies see better udder health status and higher milk yield in dairy cows.
Conclusion
Maintaining a normal somatic cell count in cows supports healthy udders and high-quality milk. Regular SCC monitoring helps farmers detect mastitis early, reduce treatment costs, and improve milk yield.
Healthy cows with low SCC produce more milk and have better reproductive performance.
Proactive management with somatic cell counter for milk increases farm profitability and ensures safer dairy products for consumers.
FAQ
What Is Considered a Normal Somatic Cell Count in Cow?
A normal somatic cell count in cow is usually below 200,000 cells per milliliter. This level indicates healthy udders and high milk quality. Farmers use this value as a benchmark for herd health.
How Often Should Farmers Test Somatic Cell Count?
Farmers should test somatic cell count at least every two weeks. Regular testing helps detect udder health problems early. Many farms use automatic sensors for even more frequent monitoring.
Can High Somatic Cell Count Affect Milk Quality?
Yes, high somatic cell count can lower milk quality. It often leads to reduced milk yield, poor flavor, and shorter shelf life. Processors may pay less for milk with high SCC.
What Are the Main Causes of Increased Somatic Cell Count?
The main causes include udder infections, poor hygiene, and improper milking techniques. Stress and injury can also raise somatic cell count. Farmers should address these issues quickly.
How Can Farmers Lower Somatic Cell Count in Their Herds?
Farmers can improve hygiene, use proper milking routines, and separate infected cows. Regular SCC monitoring and early mastitis detection also help maintain low somatic cell counts.
