Dairy cows that are fed flaxseed produce more nutritious milk, according to a new study at Oregon State University.
Their milk contained more omega-3 fatty acids and less saturated fats, the study found. Diets high in saturated fat can increase cholesterol and cause heart disease, while those rich in omega-3 and other polyunsaturated acids may reduce the risk of heart diseases, studies show.
Traditional cattle feed mixtures of corn, grains, alfalfa hay and grass silage result in dairy products with low concentrations of omega-3 and other polyunsaturated fats, according to Gerd Bobe, the lead scientist in the study, which has been published in the "Journal of Dairy Science."
Ten pregnant cows at OSU's dairy were fed different amounts of flaxseed – up to 7% of their daily diet. Researchers attempted to pinpoint the amount of flaxseed that would maximize the amount of omega-3 in milk and other dairy products without negatively impacting the production and product texture.
"We were looking for sweet spot," says Bobe, an expert in animal and human nutrition. "Too much of a good thing can be bad, especially when trying to maintain consistency in dairy products."
Collaborators in OSU's food science and technology department assisted in turning milk into butter and fresh cheese, which were then tested for texture and nutritional composition. They found that feeding cows up to six pounds of extruded flaxseed improve the fat profile without negatively affection the production and texture of milk and other dairy products.
The extrusion processes uses heat to press raw ground flaxseed into pellets for cattle consumption.
At six pounds a day, saturated fatty acids in whole milk dropped 18%, poly-unsaturated fatty acids increased by 82%, and omega-3 levels rose 70% compared to results of cattle fed no flaxseed. Similar improvements were observed in butter and cheese.