I often use calf liver for home made dog food. Calves are usually fed grass and thereby should be less contaminated from soy and corn in their diets. You can give it to dogs once a week as a snack or slice some up to combine with daily mix.
Carnivores like dogs and cats require organ meats in their diets to stay healthy. I believe many of the diseases people's little friends get are often as a result of deficiencies of the nutrients supplied by liver, such as high amounts of real retinol (vitamin A). Cats cannot convert beta carotene to vitamin A in the body, so they really need real organ meats.
Humans could also add calf liver to their diet as an alternative to local pasture-raised, if this was hard to come by. Cook liver with onions and bacon in pan or on the grill, or you could make delicious liver pate with vegetables like sweet potatoes and carrots and fresh cream and yogurt.
Following Weston A. Price