Parity affect somatic cell count in dairy cows. Higher parity often leads to increased somatic cell count, which can impact both milk yield and udder health. Farmers who use a somatic cell count tester and maintain solid management practices help control this issue across different parities. The following table demonstrates how parity influences milk loss at various lactation stages:
| Parity | Milk Loss (kg/d) at Early Lactation | Milk Loss (kg/d) at Mid-Lactation | Milk Loss (kg/d) at Late Lactation |
|---|---|---|---|
| 1 | 0.68 | 0.55 | 0.97 |
| 2 | 1.47 | 1.09 | 2.45 |
Key Takeaways
- Higher parity in dairy cows often leads to increased somatic cell count, which can negatively impact milk yield and udder health.
- Regular monitoring of somatic cell count helps farmers detect issues early, allowing for timely interventions to maintain milk quality.
- Effective management practices, such as good hygiene and selective dry cow therapy, are crucial for controlling somatic cell count, especially in older cows.
- Understanding the relationship between parity and somatic cell count enables farmers to make informed decisions about herd management and improve profitability.
Parity Affect on Somatic Cell Count
SCC Changes with Parity
Parity affect the somatic cell count in dairy cows throughout their productive lives. As cows experience more calvings, the somatic cell count (SCC) in their milk tends to rise. Researchers have measured this trend by tracking SCC across different parities. The following table shows how the mean SCC increases as cows move from their first to later lactations:
| Parity | Mean SCC (cells/ml) |
|---|---|
| 1 | 44.7×10^3 |
| 2 | 50.9×10^3 |
| 3 | 53.0×10^3 |
| >4 | Increased significantly (p<0.05) |
This pattern means that each additional lactation brings a higher risk of elevated somatic cell count. The increase in SCC reflects changes in the udder and immune system as cows age. High somatic cell count often signals inflammation or infection, which can reduce milk quality and yield. Studies show that high-parity cows are more likely to develop chronic mastitis. Chronic mastitis leads to a sharp drop in milk yield. For example, milk production can fall from over 35 kg per day to less than 15 kg per day—a decrease of nearly 60%—when SCC is high and the proportion of certain somatic cells is low. These changes also affect milk composition, including lactose, fat, and protein levels.
Note: Monitoring SCC at each lactation stage helps farmers detect problems early and protect milk quality.
Primiparous vs. Multiparous Cows
The difference in somatic cell count between primiparous (first-lactation) and multiparous (multiple-lactation) cows is clear in large-scale studies. Primiparous cows usually have lower SCC and fewer mastitis events. Multiparous cows, especially those in their third or later lactations, show higher SCC and a greater risk of udder infections. The following table summarizes SCC levels by group:
| Group | Median SCC (cells/mL) | IQR (cells/mL) |
|---|---|---|
| Primiparous | 18,000 | 7,000 to 52,000 |
| Multiparous | 40,000 | 16,000 to 128,000 |
| All cows | 30,000 | 13,000 to 113,000 |
| Statistical | Higher for multiparous than primiparous (P < 0.001) |
Multiparous cows not only have higher average SCC but also a greater chance of exceeding critical thresholds. In commercial herds, 27.7% of multiparous cows have SCC above 250,000 cells/mL, compared to only 8.8% of primiparous cows. The risk of very high SCC (over 400,000 cells/mL) is also much greater in multiparous cows.
| Cow Type | SCC >250,000 cells/mL | SCC >400,000 cells/mL |
|---|---|---|
| Primiparous | 8.8% | 4.1% |
| Multiparous | 27.7% | 14.3% |
Parity affect not only the average somatic cell count but also the likelihood of severe udder health issues. Second-parity cows often show the lowest SCC and best udder health, while third-parity and older cows face higher risks. Genetic factors also play a role. The heritability of somatic cell count increases from first to second parity, then drops slightly in later parities. This means that genetic selection for low SCC can be more effective in cows during their second lactation.
| Parity | Heritability LSCC | Heritability LTSCC |
|---|---|---|
| First Parity | 0.03 | 0.06 |
| Second Parity | 0.20 | 0.19 |
| Later Parities | 0.11 | 0.15 |
Farmers who understand how parity affect somatic cell count can make better decisions about herd management. Regular SCC testing and targeted interventions for high-parity cows help maintain milk quality and reduce losses.
Factors Behind SCC Increase
Udder Health and Aging
As cows age and experience more lactation cycles, their udder health faces new challenges. Changes in udder tissue and immune function play a major role in the rise of somatic cell count. Older cows often show more wear in udder tissue, which can make them more vulnerable to infections. The immune system also weakens with age, making it harder for cows to fight off bacteria that cause mastitis. High-yielding cows face even more stress, which can lower immune defenses and increase the risk of infection. The table below highlights how age, parity, and milk yield relate to higher somatic cell count:
| Factor | Observation |
|---|---|
| Age > 8 years | Significantly higher SCC (p = 0.007) |
| Parity ≥ 5 | Significantly higher SCC (p = 0.004) |
| High-yielding cows | More vulnerable to IMI and higher SCC due to stress and lower immunity |
These biological changes mean that parity affect both the structure of the udder and the cow’s ability to resist disease. Each new lactation brings more risk, especially for cows with high milk output. Farmers must pay close attention to udder health in older cows to keep somatic cell count low and maintain milk quality.
Management and Hygiene
Management and hygiene practices have a strong impact on somatic cell count, especially in cows with higher parity. Effective dry cow management, careful milking routines, and proper cow preparation help keep SCC under control. Farms that use selective dry cow therapy and focus on mastitis prevention see better udder health and lower somatic cell count. The environment during the dry period also matters. Clean, comfortable stalls and good bedding reduce the risk of infection between lactation cycles.
Poor hygiene can quickly lead to higher somatic cell count in multiparous cows. Key factors include:
- Longer standing times after milking allow teat canals to close, lowering the risk of bacteria entering the udder.
- Clean stalls and bedding prevent cows from lying down in dirty areas, which reduces exposure to harmful bacteria.
Environmental factors also interact with parity to influence somatic cell count. Individual cow traits, stage of lactation, age, daily milk yield, milking rate, and the fat-to-protein ratio all play a part. Both genetics and environment shape SCC patterns in dairy herds. Farmers who understand these links can adjust management to protect udder health and keep somatic cell count within safe limits.
Tip: Regular monitoring of somatic cell count and close attention to hygiene help prevent udder health problems, especially in older cows with many lactations.
Somatic Cell Count and Milk Quality
Milk Loss and Quality Issues
Elevated somatic cell count in cows directly impacts milk quality and milk yield. When SCC rises, milk composition changes. Fat, lactose, and casein decrease, while whey protein, lactoferrin, sodium, and chloride increase. These changes lower the nutritional value and alter the taste of milk. High SCC can cause off-flavors, such as rancidity, bitterness, or a salty taste. Enzyme activity also increases, which can break down milkfat and protein, further reducing quality.
| Effect on Milk Quality | Description |
|---|---|
| Changes in Composition | High SCC leads to decreased fat, lactose, casein, and increased whey protein, lactoferrin, sodium, and chloride. |
| Sensory Attributes | High SCC can cause off-flavors such as rancidity, salty taste, and bitterness. |
| Enzyme Activity | Elevated SCC correlates with increased lipases and proteases, affecting milkfat and protein. |
| Financial Implications | High SCC can result in loss of quality premiums and market access for producers. |
Milk yield drops as SCC increases. Multiparous cows lose more milk than primiparous cows. For every twofold increase in SCC, primiparous cows lose about 0.4 kg of milk, while multiparous cows lose 0.6 kg. Over a lactation, this means a loss of 80 kg for primiparous and 120 kg for multiparous cows. First-parity animals experience 45% less milk loss compared to older cows. These losses highlight how parity affect both milk yield and quality.
SCC above 200,000 cells/mL often signals udder infection. Milk with SCC over 400,000 cells/mL is unfit for human consumption in the EU. Legal thresholds vary by country, but high SCC always reduces milk quality.
Mastitis Risk By Parity
Mastitis risk rises with both SCC and parity. Older cows, especially those with four or more lactations, face a much higher risk of mastitis. In Holstein cows, parity of four or more increases the risk of subclinical mastitis by nearly four times. Jersey cows show a similar trend, with risk more than doubling. Longer days in milk and lower milk yield also raise mastitis risk. Multiparous cows have a higher chance of udder health problems, which leads to more frequent mastitis cases and higher SCC.
| Factor | Effect on SCC and Mastitis Risk |
|---|---|
| Parity (≥4) | 3.9 times higher risk for Holstein, 2.2 times for Jersey |
| Days in Milk (>305) | 2.0 times greater risk for both breeds |
| Milk Yield (high vs. low) | Higher yield lowers mastitis risk |
| Milking Frequency (3/day) | Reduces mastitis risk by 10-20% |
Regular monitoring with a somatic cell count tester helps farmers detect rising SCC early. This tool allows for quick action to protect milk quality and udder health. By tracking SCC, farmers can target high-risk cows, especially those with higher parity, and reduce the need for antibiotics. Monitoring supports better management and helps maintain both milk yield and quality across the herd.
Using a somatic cell count tester ensures that milk meets quality standards and helps prevent mastitis, especially in older cows.
Managing SCC by Parity
Monitoring Tools and Testers
Advances in somatic cell count testing technology help dairy farmers manage udder health in cows of all parities. Tools like the somatic cell counter for milk and the QScout® Farm Lab provide rapid results, allowing producers to make timely decisions about treatment or culling. Differential somatic cell counts (DSCC) give a deeper look at udder infections by showing the types of white blood cells present. This information helps farmers target cows with high risk of treatment failure and adjust management strategies. Regular use of a somatic cell count tester supports early detection of problems, which protects milk yield and quality.
| Key Management Practice | Description |
|---|---|
| Infection Status | Checking the mammary gland for infection is the most important step. |
| Diurnal Effects | Sampling at different times of day improves accuracy of SCC data. |
| Linear Score Threshold | A linear score of 5 (283,000) is a good cutoff for mastitis control. |
| Lactational Average | Using average scores over a lactation gives reliable estimates for each cow. |
| Treatment of Subclinical Mastitis | Treating based only on SCC is not cost-effective and is not recommended. |
Regular SCC testing with modern tools helps dairy farmers maintain high milk quality and reduce production losses.
Strategies for Different Parities
Dairy cows of different parities need tailored management to control somatic cell count and protect milk production. High-parity cows face greater risks of mastitis and higher SCC, so preventive care and hygiene become even more important. Farmers should focus on these strategies:
- Use selective dry cow therapy for cows with SCC above 200,000 cells/mL, especially in older cows.
- Apply the ‘graze 2, rest 4’ method after calving to lower mastitis risk.
- Keep dry cow and calving areas clean to maximize hygiene.
- Group cows by mastitis origin to spot management gaps.
- Aim for more than 80% of dairy cows with linear scores of 3 or lower.
- Form a team with veterinarians and milk quality experts for ongoing SCC management.
Subclinical mastitis and high SCC can cost dairy farms over $1 billion each year in the U.S., with losses of $110 per cow. Continuous monitoring and preventive care reduce the need for antibiotics and support better milk yield. Farmers who use a somatic cell count tester and follow evidence-based protocols can maintain healthy dairy cows and strong milk production across all parities.
Conclusion
Parity plays a major role in a cow’s somatic cell count, which directly affects milk quality and udder health. Regular SCC monitoring helps farmers detect intramammary infections early and track immune cell levels in milk. Differential SCC offers even more insight for udder health management.
- High SCC reduces milk yield and quality.
- Financial losses from high SCC can reach $533 per farm in three months.
- Treating affected cows is more cost-effective than culling.
Farmers who use somatic cell count test kit and maintain strong hygiene protect herd health and improve profitability.
FAQ
What Is Parity in Dairy Cows?
Parity refers to the number of times a cow has given birth. Farmers use parity to group cows as primiparous (first calving) or multiparous (multiple calvings). Parity helps track changes in milk production and udder health.
Why Does Somatic Cell Count Increase With Parity?
Older cows experience changes in udder tissue and immune function. These changes make them more likely to develop infections, which raises somatic cell count. High parity cows often face more stress and exposure to bacteria.
How Can Farmers Monitor Somatic Cell Count Effectively?
Farmers use somatic cell count tester for regular monitoring. These tools provide quick results. Early detection allows for timely treatment and better management of udder health. Many farms also use differential SCC tests for deeper analysis.
Does High Somatic Cell Count Always Mean Mastitis?
A high somatic cell count often signals inflammation or infection, but not always clinical mastitis. Subclinical mastitis can raise SCC without visible symptoms. Farmers should use SCC results with other health checks for accurate diagnosis.
What Management Practices Help Lower SCC in Older Cows?
Good hygiene, selective dry cow therapy, and regular SCC testing help control somatic cell count. Farmers should keep bedding clean, monitor high-risk cows closely, and work with veterinarians to develop targeted prevention plans.