The breed of dairy cows affects butterfat supplies, too. The Dairy Herd Improvement Association has records on about 60 percent of Georgia's dairy herd. They test the milk from members' herds and keep records on the cows. Holsteins' milk has about 3.5 percent butterfat. There is a tradeoff, though.
Jerseys produce less milk volume.
But that decision could pay off in the long run. Sometimes people go back to butter for the taste. And sometimes they switch because of concerns about trans-fatty acids, which can be high in stick margarine. Crawley said trans-fatty acids may be as likely to raise blood cholesterol levels as saturated fat. If you use margarine or butter fairly often, you may want to choose soft or liquid margarine.