According to a study published in the Journal of Dairy Science in January of 2013, dairy cows fed 6 pounds of flaxseed per day have more nutritious milk. Traditional feed contains GMO corn and grains, alfalfa hay, and grass silage; the milk has low amounts of omega-3 fatty acids and other polyunsaturated fats, and is high in saturated fats.
Flax fed cows were found to have 18% less saturated fat, 82% more polyunsaturated fats, and 70% more essential fatty acids. Milk production was otherwise unaffected.
