DNA Markers Show Lasting Effects of Cow Transition Disease

By Blake Jackson

Sydney Jewell ’26, a doctoral student in the Department of Animal Science, conducts research in the lab of Associate Professor Heather Huson, focusing on how epigenetics influences dairy cattle health. Jewell work examines how environmental factors and stressors can alter gene expression without changing the DNA sequence itself.

Epigenetics encompasses the mechanisms that regulate when and where genes are expressed. While an animal’s genome contains all the instructions needed to make proteins, only select genes are activated in specific tissues or situations.

Jewell compares the genome to a cookbook full of recipes: epigenetic markers act like sticky notes identifying which recipes - or genes - will be used, influenced by stress and environmental conditions.

Jewell’s research centers on the dairy cow transition period, the stressful window surrounding calving and early lactation. This stage is closely linked to transition diseases such as ketosis, which can reduce milk production, fertility, and long-term performance. She and her colleagues suspect that lingering effects from these diseases may stem from epigenetic changes formed during illness.

To investigate, the team collected blood samples from first-lactation cows both before calving and one month into lactation. They compared healthy cows with those diagnosed with subclinical ketosis. Their analysis revealed shifts in DNA methylation - a key epigenetic mechanism in genomic regions associated with ketosis, suggesting that gene expression may remain altered even after recovery.

Jewell also explored whether transition diseases impact the next generation. Calves born to cows that previously experienced metritis showed distinct DNA methylation patterns at birth, particularly in regions related to growth and immune function, indicating potential long-term consequences.

Jewell has presented these findings at major scientific conferences and is preparing multiple research papers. Ongoing work includes a companion study designed to confirm the observed methylation patterns and link them with actual gene expression changes in additional animals.

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