An Iowa State University study has shown that milk and beef from pastured cattle have higher concentrations of conjugated linoleic acid (CLA) than result from feeding stored forages.

Beef and milk are two of the main sources of CLA, a fatty acid thought to help prevent cancer, diabetes and obesity. Iowa State researchers documented the concentrations of CLA in beef and milk from farms in northeastern Iowa and southwestern Wisconsin. The study involved four beef and 12 dairy farms. CLA was measured as a percentage of the total fatty acids in the meat and milk.

One of the beef producers used pasture; the others fed stored forages. Meat from grazed cattle had from 0.34% to 0.46% CLA; meat from cattle fed stored forages had 0.23-0.33% CLA.

Among the dairy farms, the average concentrations of CLA over the course of the study were 0.35% in Iowa and 0.27% in Wisconsin. CLA fluctuated, with the highest concentra-tions being found in May and June and the lowest in winter, when stored forages were fed. In June, one farm in Iowa and one in Wisconsin had CLA concentrations over 1.3%.

“This study helps confirm on the farm what has already been found to be true in a labo-ratory,” says Allen Trenkle, Iowa State animal scientist. “I think there’s potential of these products having greater value if they can maintain their identity on the market.”