Good immune functions could enhance cow milk quality and health

Researchers have identified various distinctive immune cells in cow’s milk, creating potential avenues for enhancing animal health and milk production—as detailed in a study in Animal Nutriomics.

Using single-cell RNA sequencing to study fresh milk samples, the researchers were able to explore the molecular identities of cow milk in greater detail, particularly immune cells, where they discovered that T cells and granulocytes were present as the main cell types in healthy Holstein cows.

The study of immune cell subpopulations in cow’s milk offers greater insight into cows’ mammary gland immune function, which in turn influences cow health and milk quality.

Lead researcher Gabriela Perez-Hernandez, of Virginia Polytechnic Institute and State University in the U.S., said, “Our study highlights the presence of immune and secretory mammary cells in cow milk and underscores their significance for understanding mammary gland function and health. Our findings lay the groundwork for future studies aimed at uncovering the molecular mechanisms that influence milk production and glandular health.

“This research is important, because understanding mammary gland biology better can help us improve livestock productivity and milk quality. Ultimately, our research is helping to build more sustainable and efficient milk production practices, with potential benefits for both the agricultural industry and human nutrition.”

The recent development of technologies like single-cell RNA sequencing, which can identify low-abundance cell types and compare the natures of individual cells within a varied sample, has made tracing molecules at the individual cell level highly relevant to better understanding how cows produce milk.

To conduct this study, the researchers—all based at Virginia Tech—brought together twenty-five healthy Holstein cows of different lactation stages, milk yields, and pregnancy statuses. Throughout the six-month, non-invasive experiment, the cows remained in the main milking dairy herd and were housed in a sand-bedded free-stall barn at the Virginia Tech Dairy Science Complex–Kentland Farm, in Blacksburg, Virginia, where they were milked twice daily for science.