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Dairy DNA

For over 30 years,  Sprout Creek Farm has honored and lived by healthy eating, especially when consuming dairy. As our summer season begins, Sprout Creek Farm looks to its students for advice on steps we can take to ensure the quality and wholesomeness of our milk. This week, a group of inquisitive learners flew in from Sacred Heart Atherton in California to spend the week at Sprout Creek. During their stay, they used their thinking caps to test cow DNA and ensure the quality of our dairy.

Some Background

To all the milk fanatics out there, the alleged health differences between A1 and A2 milk is common knowledge. To the rest of us, however, an explanation is needed. "Beta Casein is the main protein found in all milk," says Diane Sweeney, Science Department Chair at Sacred Heart, "but the type of Casein splits into A1 milk and A2 milk." In other words, A2 and A1 are the different proteins that make milk milk!  According to Sweeney, this difference is a hot topic — many have attested to the great benefits of drinking A2 milk instead of A1 milk, even though A1 is the more common of the two. Sweeney also challenges notions that the difference between these branches of milk could cause serious health problems, but believes that significant research does show that A2 could be better for the gut.  Regardless of how substantial the argument against A1 may or may not be, testing our milk for A2 would certify our milk as easier to digest (from our own experience, it goes down pretty smooth.) That's where our student scientists come in handy.

The Process

Now that we're done briefing this scientific operation, we can explore the neat procedure of testing cow DNA for certain proteins. Exploring science in both the barn and the laboratory, these students used the scientific method to examine DNA:

  1. First, students from Atherton plucked hairs from baby cows, milking cows, yearlings, and cows out in the pasture.
  2. After they're done collecting cow hairs, students pipette DNA from the follicle of each hair into a string of tubes.
  3.  Using a technique known as Polymerase chain reaction, students copy each gene to prepare for the final step, where they'll be able to seperate bands of DNA  and observe differences.
  4. Using gel electropheresis, students create a DNA fingerprint, alllowing them to identify common and uncommon proteins between different cows. As the final step in the process, this is where the big reveal happens: A1 or A2?


The results

After comparing samples, students gathered their results and produced a conclusion.

One set of our cows tested positive for A2 milk,  the other inconclusive. Despite these inconsistencies, Mrs. Sweeney reflects on a positive exploration of the scientific method for her students.  Learning the importance of procedure and method at an early age will allow these students to develop into the next great scientists, engineers, researchers, and life long learners.

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