Calcium is a naturally occurring mineral found in a cow’s diet, such as in feed and water. When a cow eats foods containing calcium, it is absorbed into the cow’s bloodstream and transported to the mammary glands, from where it is secreted as part of the milk. Dairy products, such as milk, cheese, and yogurt, are well-known sources of calcium in human nutrition. The calcium content in milk can vary depending on the cow’s diet and health condition.