A high SCC often signals subclinical mastitis, even when cows appear healthy. Early detection protects both milk quality and herd health. Studies show that for every rise of 100,000 SCC, each cow can lose 5.5 pounds of milk daily.
- Reduced milk production, lower pregnancy rates, and higher death losses occur with elevated SCC.
- Failing to catch subclinical mastitis early leads to significant financial losses, mainly from decreased milk yield and increased veterinary costs.
Routine use of a somatic cell count tester helps farms spot problems before they escalate, supporting both animal well-being and farm profitability.
Key Takeaways
- High somatic cell count (SCC) often indicates subclinical mastitis, even when cows appear healthy. Regular monitoring helps catch issues early.
- For every increase of 100,000 SCC, cows can lose about 5.5 pounds of milk daily. Early detection protects both milk quality and farm profits.
- Using a somatic cell count tester allows farmers to monitor SCC frequently. This helps identify trends and take action before problems escalate.
- Maintaining clean bedding and following strict milking procedures can reduce the risk of high SCC. Good management practices support overall herd health.
- Regular SCC testing is crucial. It helps farmers detect subclinical mastitis early, ensuring better milk quality and preventing financial losses.
High SCC Explained
What Is SCC?
Somatic cell count (SCC) measures the number of somatic cells in each milliliter of milk. These cells include macrophages, polymorphonuclear leucocytes (PMN), lymphocytes, and epithelial cells. In healthy cows, macrophages dominate, while unhealthy cows show more PMN. SCC serves as a key indicator of udder health. A low SCC means the udder is healthy and milk quality is high. When cows develop mastitis, the SCC rises as the immune system sends more cells to fight infection.
Table: SCC and Dairy Cow Health
Definition of Somatic Cell Count (SCC) Implications for Dairy Cow Health and Milk Quality SCC is quantified as the number of somatic cells per ml of milk. A lower SCC indicates better animal health, as somatic cells originate from the udder. An SCC of 100,000 or less indicates an ‘uninfected’ cow. Higher SCC levels can indicate mastitis, affecting milk production and quality. An SCC of 200,000 suggests potential infection with mastitis. Milk with an SCC over 400,000 is unfit for human consumption.
Measuring SCC
Farmers and veterinarians use several methods to measure SCC. The California Mastitis Test (CMT) offers a quick, on-farm check with 83.1% agreement and 81.0% sensitivity. The DeLaval cell counter provides high specificity at 97.5%. Direct detection methods, such as flow cytometry, deliver the most accurate results but require specialized equipment and higher costs. Many farms now use a somatic cell count tester for routine monitoring. This device gives fast, reliable SCC readings, helping identify high SCC before it affects the bulk milk somatic cell count.
- Common SCC Measurement Methods:
- California Mastitis Test (CMT)
- DeLaval cell counter
- Porta SCC
- Laboratory-based flow cytometry
A somatic cell count tester allows for frequent checks, making it easier to spot trends and take action early.
Normal vs. High Levels
SCC thresholds help determine udder health and milk quality. An SCC below 100,000 cells/mL signals a healthy cow. When SCC rises above 200,000 cells/mL, the risk of subclinical mastitis increases. Industry standards set 250,000 cells/mL as a diagnostic point for high SCC. Milk with SCC over 400,000 cells/mL is considered unfit for human consumption. The bulk tank somatic cell count should stay below 310,000 cells/mL to avoid financial penalties and ensure milk quality.
| SCC Level (cells/mL) | Health Status | Impact on Milk Production |
|---|---|---|
| <100,000 | Healthy, uninfected | Normal |
| 200,000 | Possible infection | Decreased |
| 250,000 | Diagnostic for high SCC | Noticeable loss |
| 310,000 | Subclinical mastitis likely | Bulk milk somatic cell count threshold |
| 400,000+ | Serious infection | Milk unfit for sale |
High SCC signals a problem even before visible symptoms appear. Regular monitoring with a somatic cell count tester helps keep SCC low, protecting both herd health and farm profits.
Subclinical Mastitis
What It Is?
Subclinical mastitis affects dairy cows much more often than clinical mastitis. This condition does not show visible symptoms in the milk or udder, making it difficult for farmers to detect during daily routines. The infection persists longer than clinical cases and often serves as a hidden source of pathogens that can spread to healthy cows. Subclinical mastitis usually results from bacteria such as Streptococcus agalactiae, Staphylococcus aureus, Escherichia coli, and other common pathogens. These bacteria trigger an immune response, but the cow’s milk and udder look normal. Because of this, many cases go unnoticed, leading to ongoing problems in the herd.
Diagnosis by SCC
Farmers and veterinarians rely on SCC to diagnose subclinical mastitis. A high SCC in milk samples signals the presence of infection, even when cows appear healthy. The most common threshold for detecting subclinical mastitis is 200,000 cells per milliliter. At this level, sensitivity reaches 74% and specificity reaches 89%, making scc a reliable tool for herd health monitoring.
| SCC Threshold (cells/mL) | Sensitivity (%) | Specificity (%) |
|---|---|---|
| 200,000 | 74 | 89 |
A bulk milk SCC between 100,000 and 200,000 cells/mL suggests that about 20% of the herd has subclinical mastitis. As scc increases, the percentage of affected cows rises. For every 100,000 cell increase, the prevalence of subclinical mastitis can climb by about 15% to 20%. This pattern highlights the importance of regular scc testing to catch infections early.
Why Symptoms Are Hidden?
Subclinical mastitis does not cause visible changes in the milk or udder. The immune system responds to infection, but the reaction remains mild and does not produce obvious signs. The specific bacteria involved and the cow’s immune response both play a role in hiding symptoms. This lack of visible clues makes high SCC the main warning sign for subclinical mastitis. Farmers who rely only on visual checks may miss many cases, leading to economic losses from reduced milk yield and quality.
Note: Subclinical mastitis often goes undetected without scc testing. Regular monitoring helps protect herd health and milk quality.
High SCC and Mastitis Link
Immune Response
The biological process behind high scc begins when bacteria invade the udder. The cow’s immune system detects these pathogens and responds quickly. Epithelial cells and macrophages recognize the bacteria through specialized receptors called Toll-like receptors. This recognition activates the NF-κB signaling pathway, which leads to the production of pro-inflammatory cytokines and chemokines. These molecules signal more immune cells, especially neutrophils, to migrate to the site of infection.
- Immune responses triggered by bacterial infections lead to the migration of immune cells to the udder.
- Inflammatory mediators are produced as a result of these immune responses.
- Epithelial cells and macrophages recognize pathogens through Toll-like receptors, initiating the NF-κB signaling pathway.
- This pathway stimulates the production of pro-inflammatory cytokines and chemokines, recruiting additional immune cells like neutrophils to the udder.
- The severity of the immune response varies with the type of pathogen, influencing the somatic cell count.
During mastitis, the permeability of the blood-milk barrier increases. Damage to mammary tissue allows more immune cells to enter the milk, raising the SCC. In healthy udders, macrophages and lymphocytes dominate. When infection occurs, neutrophils become the main cell type, causing a high scc. The effectiveness of the immune response determines how quickly the cow can clear the infection and return to normal SCC in cows.
Note: Increased scc signals an active immune response in the udder. High SCC above 100,000 cells/mL suggests infection, while levels above 200,000 cells/mL indicate a clear case of intramammary infection.
Research Evidence
Many studies confirm the link between high SCC and subclinical mastitis. Researchers have found that subclinical mastitis is characterized by an increase in SCC in milk. This rise serves as a critical factor for identifying the condition. The following table summarizes key findings from recent research:
| Study Title | Findings |
|---|---|
| Association between somatic cell count or morbidity of chronic subclinical mastitis and longevity in dairy herds in Eastern Hokkaido, Japan | Significant variations in herd somatic cell count levels and chronic subclinical mastitis morbidity were found, indicating a positive correlation between high scc and subclinical mastitis. |
| Prevalence and risk factors associated with high somatic cell count in Chinese dairy herds | The study emphasizes the importance of controlling subclinical mastitis, with scc being a key indicator. |
Researchers in China and Japan highlight that SCC is a reliable marker for subclinical mastitis. The studies show that herds with high SCC experience more cases of subclinical mastitis and face greater risks to milk quality and cow longevity.
- Somatic cell count is used as an indicator of raw milk quality and udder hygiene.
- Normal SCC levels for healthy quarters and composite milk should not exceed 100,000 cells/mL.
- An scc above 200,000 cells/mL is considered abnormal.
- Legal limits for scc vary by country: 300,000 cells/mL in China and the EU, 400,000 cells/mL in Australia, New Zealand, and Canada, 500,000 cells/mL in Brazil, and 750,000 cells/mL in the USA.
The industry sets strict standards for scc to protect milk quality. High SCC not only signals subclinical mastitis but also affects farm profitability and animal health. Farms that monitor scc closely can detect problems early and take steps to reduce the impact of mastitis.
Tip: Regular scc testing helps farmers maintain milk quality and avoid penalties. High SCC should prompt immediate action to investigate and manage udder health.
What to Do About High SCC?
Monitoring Steps
Effective udder health management starts with regular monitoring of SCC in the herd. Farmers should use a somatic cell count tester to check individual cows and bulk milk samples. Monthly SCC testing helps identify cows with high SCC, but more frequent checks allow for earlier detection of subclinical mastitis. On-farm testing solutions make it practical to monitor scc without high costs. Farmers should keep detailed records of each cow’s scc history to spot trends and take action quickly.
| Testing Frequency | Benefit | Limitation |
|---|---|---|
| Monthly | Routine identification | May miss early cases |
| More Frequent | Earlier diagnosis possible | Needs affordable on-farm solutions |
Tip: Consistent use of a somatic cell count test kit supports early intervention and better udder health management.
Management Actions
When high SCC is detected, immediate steps can protect milk quality and herd health. Farmers should maintain clean, dry bedding and follow strict milking procedures. This includes pre-milking teat cleaning, post-milking teat dipping, and using clean towels for each cow. Milking machines must be well maintained to prevent injury and infection. Cows with repeated high scc may need treatment, drying off, or culling based on their health history. Dry cow therapy, either blanket or selective, can lower the risk of future infections.
- Monitor individual SCC and health records.
- Evaluate previous treatments and mastitis history.
- Decide on treatment, drying off, or culling.
- Apply dry cow therapy and teat sealants as needed.
Prevention
Prevention focuses on reducing the risk of high SCC through strong udder health management. Farmers should provide balanced nutrition, maintain a clean environment, and ensure proper ventilation. Reducing milk yield before dry-off and using post-milking dips help lower infection risk. Vaccination programs and collaboration with veterinarians support herd health. Good management practices, such as minimizing stress and providing comfortable resting areas, also play a key role.
| Preventive Measure | Description |
|---|---|
| Proper Nutrition | Balanced diets to support immune function |
| Clean Environment | Regular cleaning of bedding and housing |
| Dry Period Management | Hygiene and therapy during the dry period |
| Good Management | Consistent routines and stress reduction |
Note: Preventive strategies help keep SCC low and reduce the impact of high SCC on milk production.
Conclusion
High SCC acts as a reliable early warning sign for subclinical mastitis, even when cows show no visible symptoms. The table below highlights how SCC levels relate to udder health:
| SCC Range (cells/mL) | Udder Health Status |
|---|---|
| 0–200,000 | Healthy |
| 200,000–500,000 | Subclinical Mastitis |
| >500,000 | Clinical Mastitis |
Regular monitoring supports early detection and better milk quality. Farmers who use a somatic cell counter for milk can manage udder health more effectively and reduce milk losses.
FAQ
What Causes a High Somatic Cell Count in Milk?
Bacterial infections in the udder often cause a high somatic cell count. The cow’s immune system sends more white blood cells to fight the infection. This response increases the number of somatic cells in the milk.
How Can Farmers Lower High SCC Levels?
Farmers can improve milking hygiene, maintain clean bedding, and treat infected cows. Regular use of a somatic cell count tester helps identify problems early. Good nutrition and stress reduction also support udder health.
Why Does Subclinical Mastitis Not Show Visible Symptoms?
Subclinical mastitis triggers a mild immune response. The infection does not cause swelling or changes in the milk. Farmers cannot see signs without testing, so regular monitoring becomes essential.
Is Milk with High SCC Safe for Human Consumption?
Milk with a somatic cell count above 400,000 cells/mL is not considered safe for human consumption. High SCC often means the milk contains more bacteria and lower quality components.
How Often Should Scc Be Tested on a Dairy Farm?
Many experts recommend monthly SCC testing for each cow. More frequent testing allows for earlier detection of problems. On-farm testers make it easier to monitor SCC and protect herd health.