Decoding Ewe's Milk: How Somatic Cell Counts Impact Quality and Your Cheese
"Unlock the secrets of raw ewe's milk: Discover how somatic cell counts (SCC) affect milk yield, composition, and ultimately, the cheese on your plate."
Sheep breeding for milk, wool, and meat has a long and cherished tradition. While sheep numbers stabilize, efforts are increasingly focused on milk production, especially for cheese making. Improving milk yield and quality is paramount for dairy farmers.
One crucial aspect of achieving optimal milk production is effective breeding management. Keeping detailed information on individual animal production and health is vital for good management. However, the decline in animal milk recording in recent years—despite the benefits of crossbreeding with Lacaune sheep—highlights the need for accessible, practical strategies to enhance milk quality.
Regular milk recording primarily involves analyzing milk composition, but analysis of somatic cell counts (SCC) is less common, despite its widespread recognition as an indicator of udder health. Because milk payments aren't based on SCC, routine analysis is rare. More objective factors and clearer relationships are needed to understand how SCC affects milk quality and value.
Measuring Ewe Milk Quality Through Somatic Cell Counts
Somatic cell count (SCC) is a widely used indicator of udder health and milk quality in dairy ewes. Research on 810 bulk milk samples from 17 farms rearing Valle del Belice sheep has demonstrated that SCC, alongside total bacterial count and clotting parameters, provides a comprehensive profile of milk quality. Studies also show that nutritional strategies, such as dietary pomegranate pulp supplementation, can increase milk health quality—potentially reflected in lower SCC—without detrimental effects on milk yield, making such interventions relevant during late lactation phases.
Standard Methods for Testing Ewe Milk and Their Constraints
Standard methods for assessing ewe milk quality include microbiological testing, SCC measurement, and antimicrobial residue screening. The Delvotest method is commonly used for detecting antimicrobial residues in ewe milk, with established detection limits for 24 antimicrobial agents tested at eight concentrations across individual ewe samples. However, artisanal cheese production using raw ewe milk introduces variability, as minimal processing preserves natural microbiota but also increases contamination risks, highlighting a tension between traditional practice and standardized quality control.
Foundational Studies on Ewe Milk Quality
Early systematic surveys of ewe milk quality established the baseline parameters still used today, including SCC, bacterial counts, and coagulation properties. Research on 21 dairy ewe farms in northeastern Greece (Xanthi and Evros regions) surveyed microbiological quality and related factors, contributing foundational data on how farm-level practices influence raw milk quality. Studies on Manchega ewes further revealed that an estimated 69% of animals produced poorly coagulating milk, highlighting coagulation as a critical and variable quality trait in sheep milk.
The Study: Analyzing Somatic Cell Counts in Ewe’s Milk
A study analyzed somatic cell counts (SCC) in individual sheep milk samples under real-world conditions. Researchers collected 2,159 samples from four farms in April, May, June, and July, categorizing ewes into five SCC groups: Low (<200,000 cells/mL), Middle (200,000-400,000 cells/mL), Higher (400,000-600,000 cells/mL), High (600,000-1,000,000 cells/mL), and Mastitis (>1,000,000 cells/mL).
- SCC as an Indicator: Somatic cell counts are a key indicator of udder health in ewes.
- Impact on Milk Yield: High SCC levels, especially in the Mastitis group, can significantly reduce milk yield.
- Breed Differences: The Lacaune breed shows a higher prevalence of mastitis compared to other breeds.
- Quality Limits: Maintaining low SCC levels is crucial for developing quality standards in sheep milk production.
Diet and Feed as Levers for Ewe Milk Quality
Recent research has increasingly focused on how dietary interventions can improve ewe milk quality. A peer-reviewed study found that dietary pomegranate pulp increased milk health quality—relevant to somatic cell count metrics—without reducing milk yield, suggesting it as a strategy for improving milk quality and reducing feeding costs during late lactation. Complementary research has compared concentrate-based diets with grazed grass-based diets in sheep farms, aiming to determine how feed composition directly impacts milk quality parameters.
Stage of Lactation as a Complicating Factor
The stage of lactation is recognized as a significant factor affecting both milk yield and ewe milk quality, complicating efforts to establish universal quality benchmarks. Changes in SCC and composition across the lactation cycle mean that a single threshold for 'quality' may be misleading without accounting for where an ewe is in her lactation. This variability represents a genuine challenge for standardized quality assessment, as milk from early and late lactation periods can differ substantially in the same flock.
Ventilation, Housing, and Milk Quality Outcomes
Comparative research on ventilation regimens in sheep housing has demonstrated that environmental management directly influences milk and cheese quality. A study comparing three ventilation regimens during summer found measurable effects on air pollution in sheep houses and on the quality of both ewe milk and Canestrato Pugliese cheese. These findings underscore that somatic cell counts and milk quality are not determined by animal factors alone, but are also shaped by housing conditions and environmental management practices.
Implications for Sheep Milk Quality
The study highlights that most animals had low SCC, but emphasis should be placed on those with counts exceeding 1,000,000 cells mL-¹. While a low percentage of animals with high SCC may indicate subclinical udder health issues rather than purely physiological factors, targeted efforts can improve milk quality. Ultimately, prioritizing ewes within the first two SCC groups may drive legislative limits for sheep milk quality, benefiting dairy production.
Morning vs. Evening Milk and Yield Estimation
Research on milking-time differences has shown that Awassi ewes' morning and evening milk yields do not differ significantly, though morning cow's milk tends to have higher fat percentage and fat/protein ratios. In ewes, significant increases in protein, lactose, and solids-not-fat levels occur in morning milk, indicating that timing of milking affects compositional quality. Separately, studies estimating milk yield and lamb growth during the suckling period report satisfactory production levels, with weaning at 45 days increasing marketed milk without negatively affecting lamb growth.
Market Growth and Quality Assurance in Ewe Milk
The ewe milk powder market, particularly in Asia, is experiencing rapid growth, with Hong Kong's market valued at approximately USD 100 million and forecasted to reach USD 140 million by 2028. This commercial expansion drives demand for robust quality assurance systems, including rigorous testing for pathogens such as Listeria monocytogenes, which has been specifically reported in ewe milk and ewe milk-derived products. As the market scales, ensuring somatic cell count standards and microbiological safety becomes increasingly critical for consumer trust and trade.
Milk Constituents, Animal Measurements, and Quality Linkages
Research published in the Nigerian Journal of Animal Science has explored the relationship between milk constituents of lactating ewes and linear body measurements of their lambs, linking maternal milk quality to offspring development outcomes. This work highlights that somatic cell counts and milk composition have implications beyond the dairy itself, affecting lamb growth and productivity. Such systemic connections mean that milk quality management is embedded within broader livestock production systems rather than being an isolated parameter.
Antimicrobial Resistance Transmission Through Ewe Milk
A study examining long-acting Moxidectin in New Zealand sheep found the drug present in ewe milk almost until weaning and in lamb plasma until eight weeks of age. This finding has direct implications for both milk quality and food safety, as antimicrobial residues in milk can affect downstream products and contribute to drench resistance. The research underscores how real-world pharmacological practices in sheep farming intersect with milk composition, somatic cell counts, and consumer safety.