How a Cow makes milk
Updated: Dec 28, 2021
We drink milk, but exactly how does a cow make milk? Watch this on-farm video and learn the basics on just how a cow produces milk. https://youtu.be/tFaB5LqXHW8
We feature Everly's mother. Eve milks 140 pounds of milk or 16 gallons each day. She produces that milk in her udder. We harvest the milk through her four teats that are attached to her udder.
Eve must eat over 100 pounds of a balanced diet to get enough nutrients in her blood to make milk. Each mouthful of food travels to her stomach where it is broken down into small nutrients. The first chamber in her stomach (rumen) softens chewed plant material, which the cow burps up and chews again several times. In the next chamber, microorganisms feed on the plant material, making energy and proteins. As the feed material moves through the other chambers and into the small intestine, nutrients and excess water are absorbed into the bloodstream and then circulate to the mammary gland in the udder.
There, special secretory cells combine the nutrients with sugars from the cow’s liver to create milk in the alveoli. For each gallon of milk a cow produces, it takes 300 to 400 gallons of blood passing through her udder.
As milk is produced, the alveoli fill and the udder expands. Just before a cow is milked, we wash the udder and squeeze out a few strips of milk through her teats. This sends a signal to the cow's brain to release oxytocin which causes her alveoli to contract or squeeze. That pushes the milk lower into the collection gland so we can harvest it with a milker through her teats.
Now, this is a very simplistic explanation of a very scientific process. This milking process is the same in humans as it is in cows! Yes, if your mom nursed you as a baby, her body did the same thing to produce healthy, nutritious milk for you.
Here are resources that offer more detail about how milk is produced in cows.