Researchers at Michigan State University (MSU) have published new findings on how cattle diets influence the nutrient composition and healthfulness of beef. The study, conducted by MSU scientists Jenifer Fenton and Jason Rowntree, was published in October 2024 in npj Science of Food.
Funded by the Greenacres Foundation and supported by MSU AgBioResearch, the study analyzed the fatty acid composition and other organic compounds in grass-finished beef from cattle raised using rotational grazing. The researchers aimed to determine whether beef’s nutritional components could reliably indicate what the cattle were fed.
Accurately identifying whether cattle consumed grass, supplemental feeds, or grains based on beef composition could help authenticate grass-finished beef. Previous research from the team, published in 2022, confirmed that grass-finished beef offers nutritional benefits over grain-finished beef, including lower fat content, higher levels of omega-3 polyunsaturated fatty acids, and a more favorable omega-6 to omega-3 ratio. Maintaining a lower omega-6 to omega-3 ratio is considered beneficial for reducing inflammation and disease risk.
Seasonal changes often require farmers practicing rotational grazing to supplement cattle diets with hay, baleage (baled silage), soybean hulls, and other feeds. While the American Grassfed Association provides guidelines on approved supplemental feeds, Fenton and Rowntree aimed to develop a scientific approach for verifying grass-finished beef claims. Their analysis of fatty acids and secondary metabolites in beef samples allowed them to predict with varying degrees of accuracy what cattle had been fed.
The study examined beef from four cattle groups at MSU’s Upper Peninsula Research and Extension Center, each receiving different feed combinations. The research team achieved prediction accuracies of up to 100% in identifying hay-fed cattle, suggesting it serves as a reliable standard for supplementing fresh forage. Findings indicated that while some supplemental feeds influenced beef composition more than others, all tested feeds remained viable options.
Looking ahead, the researchers are conducting further studies to examine the effects of feeding cattle distillers grains. Collaborators from Cal Poly Pomona, Chapman University, and Utah State University are also investigating how metabolic genes respond to different diets and whether bioactive compounds from biodiverse pastures accumulate in beef. Another potential avenue of research includes studying how different beef diets impact human health and consumer dietary choices.
