Epigenetic Clues Show Health Impacts Passed to Calves
How do environmental pressures in dairy cattle and physiological stress impact gene activity without modifying the DNA sequence itself. Sydney Jewell ’26, a doctoral candidate in the Department of Animal Science at Cornell University, is advancing research in Associate Professor Heather Huson’s laboratory, examining how epigenetic mechanisms influence dairy cattle health.
Epigenetics refers to the biological systems that determine when and where genes are turned on. Although the genome includes every instruction needed to create proteins, only certain genes activate in particular tissues or under specific circumstances. Jewell illustrates the concept by comparing the genome to a cookbook filled with recipes; epigenetic markers act like sticky notes signaling which “recipes” will be used, shaped by stressors and external conditions.
Jewell research focuses on the transition period in dairy cows, the challenging timeframe around calving and the start of lactation. This stage is strongly connected to transition-related diseases such as ketosis, which often hinder milk yield, reproduction, and overall herd performance. Jewell and her team believe the lingering effects of these conditions may be tied to epigenetic changes formed during illness.
To test this idea, the group collected blood samples from first-lactation cows before calving and again one month after. They compared animals that stayed healthy with those that developed subclinical ketosis. Their findings showed notable shifts in DNA methylation—an important epigenetic regulator—within genomic regions linked to ketosis, suggesting that gene activity may remain disrupted after apparent recovery.
Jewell also examined potential impacts on calves. Newborns from cows previously affected by metritis displayed distinct methylation signatures in areas connected to immunity and growth, implying possible long-term developmental effects.
Jewell has shared her results at leading scientific conferences and is preparing multiple manuscripts. Further research aims to validate these methylation patterns and establish their relationship with actual gene expression in additional cattle.
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