Di-calcium phosphate and trace mineralized salt are examples. Topdressing 2 to 4 ounces per cow per day is another method of feeding. Vitamins are found in feeds or synthetic products. A are examples. Dairy cows need vitamins A and D which can be provided by forage and grains, supplemented with a vitamin premix, or injected.
Quality depends on when the feed was harvested and whether it is a grass or legume.
Testing your forage is the most accurate way to estimate nutrient content. Grains are relatively constant in feed value. Feeding mistakes in the dry period can affect the next lactation. Things to Do 1. List all the feeds your cow consumes.