Guests: Dr. Jack Britt, Jack H Britt Consulting

This is the first in a series of presentations given at the 2022 Tri-State Dairy Nutrition Conference. Epigenetics of different environments and reactions is the topic at hand, presented by Dr. Jack Britt of Jack H Britt Consulting.

Dr. Britt begins by clarifying that epigenetics (transmittable changes in genetic behavior of an individual), are only beginning to be understood. This is partly due to the intricacies of DNA. For instance, the expression of DNA can vary greatly and the process of synthesizing a protein is much more complex than DNA to RNA to protein. 5:32

The tendency of DNA to change over time is the focus of epigenetics, creating positive DNA changes is the focus of multiple dairy cattle studies discussed.

After pointing out that epigenetics is mainly influenced by environment and management, Dr. Britt discusses its implications by giving an example of the pregnant cow. Each pregnant cow represents three separate generations at one time: the cow, fetus, and ovaries in the fetus. 8:34

Genes multiply to produce new life and continue multiplying after birth in various types of cells. Thus, Dr. Britt notes that a change in a gene, such as when a methyl group alters DNA expression, that alteration multiplies along with the gene, creating an epigenetic effect. 11:25

Studying epigenetics is commonly done in twins, Dr. Britt gives the example of his identical twin brother. His brother died of Parkinson’s disease a few years ago, demonstrating that the disease is an epigenetic (due to environmental change) disease instead of a genetic one. 14:56

What are areas where epigenetics have significantly impacted the production of dairy cattle?

Numerous cases are detailed by Dr. Britt, one being the decrease in fertility that correlates with a body condition score loss after calving. An oocyte matures in approximately 101 days, meaning it begins to develop soon after calving, when the cow is potentially at the lowest weight. The egg produced by this cow typically dies 4-5 days after fertilization. 23:07

Technology has created improvements in environment and management factors. Dr. Britt references the University of Guelph, where a new technology is being used to monitor and distribute calves’ energy intake to ensure they consistently gain weight during weaning. 28:57

Concluding his talk, Dr. Britt poses the question: How can technology be used to create a reputable activity score of important factors among each herd? Such a score would allow for long term comparison across herds, allowing for epigenetics to estimate performance. 33:45

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