By Blake Jackson
As temperatures continue to rise worldwide, heat stress is becoming a major concern for dairy farmers. Scientists are working to understand not only how heat affects milk production but also what happens inside the cow’s body at the cellular level.
Xingtan (Vera) Yu PhD’27, a doctoral researcher in the laboratory of Jingyue (Ellie) Duan, assistant professor of functional genomics, is studying how heat stress changes the mammary gland of dairy cows.
Yu’s research aims to uncover the biological reasons behind declining milk production during hot weather and identify possible solutions through nutrition, management practices, or genetic selection.
When cows experience heat stress, they reduce feed intake, breathe faster, stand more frequently, and use additional energy to regulate their body temperature. While these responses help animals survive extreme heat, they reduce the energy available for milk production, reproduction, and immune health.
High-producing dairy cows are especially vulnerable because milk production naturally generates significant body heat.
Yu’s research focuses on the mammary gland, the tissue responsible for producing milk. This organ contains several types of cells, including milk-producing luminal alveolar cells, supportive myoepithelial cells, immune cells, and blood vessel cells. Researchers believe each cell type may respond differently to heat exposure.
To investigate these changes, Yu compared three groups of cows: those kept in comfortable conditions, cows exposed to heat stress, and cows that received reduced feed amounts similar to heat-stressed cows but remained in comfortable temperatures.
This approach helped researchers distinguish between the effects of heat itself and the impact of reduced food intake.
Using single-nucleus RNA sequencing technology, the team analyzed gene activity in thousands of individual cells. Unlike traditional RNA sequencing, which provides an average view of tissue responses, this advanced method reveals how specific cell types react to stress.
The study found that heat stress strongly affected milk-producing cells by activating cellular stress responses and reducing milk-related functions.
Researchers also discovered changes in communication between myoepithelial cells and other epithelial cells, highlighting the importance of cell interactions in maintaining mammary gland function.
The findings suggest that changes in dairy cows can begin quickly during heat exposure, emphasizing the need for early heat management strategies. The research may also help improve understanding of heat tolerance and health responses in other livestock species.
Photo Credit: gettyimages-vwalakte
Categories: New York, Education, Livestock, Dairy Cattle