Differential Direct Microscopic Somatic Cell Counts in milk from dairy cows and St Croix Sheep

Student Classification


Faculty Mentor

Mulumebet Worku, Ph.D.


Department of Animal Sciences

Document Type


Publication Date

Fall 2019


Animal Sciences


Milk contains varying number of white blood cells. These Somatic cells are the first defense against bacteria and are also determining the quality of milk. Direct Microscopic Somatic Cell Counts (DMSCCs) are an approved method for counting SCC in milk. The St. Croix sheep are known as ‘Parasitic Pasture Vacuums’ for their ability to clear a pasture of parasites reducing the need to worm sheep. They also show resistance to hoof rot. The ewes are good milkers and produce ample quantities of milk which is high in butterfat. The ewes are being milked for cheese production, in some regions of the United States. These animals are calm in roles in animal health and production. The objective of this study is to compare DMSCC in milk from St Croix Sheep compared to dariy cows. Milk samples (5 ml) were collected from (N=3 each) dairy cows and St Croix sheep at the NC A&T State University farm. Cell smears were prepared in duplicate stained using Wright’sstain and 100 cells were counted under a light microscope (). Cow and sheep milk samples contained 39 and 40% macrophages, 54% lymphocytes, and 25% neutrophils respectively. These data indicate differences or similarities in SCC in milk form St Croix sheep compared to cow milk that may impact milk quality and udder health that can impact food safety and animal welfare. Thus, further studies are warranted.

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