Organic Valley, Wisconsin, collected 1163 samples over three years of its Grassmilk, a product line of milk from entirely grass-fed cows, and had the fatty acid content analysed. The study compared the omega-3 fatty acid levels in the milk from grass-fed cows to conventional and organic milk. Researchers found that milk from grass-fed cows had 147% more omega-3 than conventional milk and 52% more than organic milk.
Omega-3 fatty acid has been shown to prevent heart disease and help control arthritis.