Somatic cell counts in goat milk should not be interpreted against a single fixed threshold, according to a review that brings together findings from 119 publications issued between 2000 and 2025. The analysis, published in Acta Veterinaria Scandinavica, says the measurement is affected by several biological and farm-level factors, making a straightforward distinction between healthy and infected udders more difficult than in cattle.
The researchers selected the papers from an initial 598 records identified through Web of Science, Scopus, PubMed and Google Scholar. Their conclusion is that a goat’s cell count can reflect physiology, genetics, season, management and infection, with the relative importance of those factors varying between animals and farms.
Why goat milk is different
The review links much of the difficulty to the way goats produce milk. Goat mammary secretion is primarily apocrine. During this process, fat globules are released with small pieces of the secretory cell’s cytoplasm attached. Those fragments generally do not contain nuclei, but they are similar in size to somatic cells and can be counted by routine methods.
The analysis gives an average concentration of about 150,000 cytoplasmic fragments per millilitre in goat milk. It therefore recommends DNA-based counting techniques for goats, which can distinguish cellular material more reliably than methods that count particles without identifying their origin.
| Animal | Typical count or range in uninfected milk | Relevant biological feature |
|---|---|---|
| Goats | 270,000 to 2,000,000 cells per millilitre | Apocrine secretion and abundant cytoplasmic fragments |
| Sheep | 10,000 to 200,000 cells per millilitre | Apocrine secretion, but about 15,000 fragments per millilitre on average |
| Cows | Roughly 100,000 cells per millilitre | Merocrine secretion without comparable cellular debris |
The figures explain why a value that might prompt concern in cow milk cannot automatically be applied to a goat herd. Sheep milk is also produced through apocrine secretion, but the review reports a much lower average concentration of cytoplasmic fragments than in goats. Cows release milk components through merocrine secretion, without the same level of cellular debris.
Cell types add another layer
The composition of the cells being counted also changes the picture. In uninfected goat milk, neutrophils account for 45% to 74% of somatic cells, while epithelial cells can make up as much as 27%. In infected goat glands, the proportion of neutrophils rises to between 71% and 86%. At the same time, macrophages fall to 8% to 18%, and lymphocytes decline from 9% to 20% in uninfected animals to 5% to 11%.
- Goat milk can show naturally high cell counts even when animals are uninfected.
- Routine particle-counting methods may include cytoplasmic fragments.
- The review supports interpreting results alongside the animal, herd and production context rather than relying on one cut-off value.
Because neutrophils are already common in healthy goats, their presence alone does not provide the same clear signal of infection as it may in other dairy species. The review consequently challenges the use of simple threshold values as a stand-alone method for assessing goat udder health or milk quality.
For dairy-goat producers and advisers, the findings underline the importance of understanding how a laboratory result was generated and what it represents in goats. The analysis points towards more specific counting methods and a broader interpretation of results, rather than transferring cattle-based expectations directly to goat milk.
