Over the past few decades many studies have revealed that pasture-feeding is much healthier for the cows and for the consumer.
Greener Pastures: How Grass-fed Beef and Milk Contribute to Health Eating by Kate Clancy is the first study to synthesize the findings of virtually every English-language study (25 were chosen for analysis) comparing the amounts of total fats, saturated fats, omega-3 fatty acids, and Conjugated Linoleic Acid (CLA) in both pasture-raised and conventionally raised beef and dairy cattle. The report also combined analyses of the nutrition, environmental, and public health benefits of grass-based farming techniques. The report found that grass-fed milk contains higher levels of omega-3 fatty acids, the so-called beneficial fats. Grass-fed milk tends to be higher in an omega-3 fatty acid called alpha-linolenic acid (ALA) that scientists have demonstrated reduces the risk of heart disease. And grass-fed milk also is higher in CLA, a fatty acid shown in animal studies to protect against cancer. CLA was discovered in 1978 by Michael W. Pariza at the University of Wisconsin while looking for mutagen formations in meat during cooking. The most abundant source of natural CLA is the meat and dairy products of grass-fed animals. Research conducted since 1999 shows that grazing animals have from 3 to 5 times more CLA than animals fattened on grain in a feedlot. Simply switching from grain-fed to grass-fed products can greatly increase your intake of CLA.