Effects of Multiple Grass- and Grain-Fed Production Systems on Beef Fatty Acid Contents and Their Consumer Health Implications
Sarah C Klopatek, Yanqing Xu, Xiang Yang, J. W. Oltjen, Payam Vahmani
Abstract
Despite the perception that grass-fed beef contains healthier fats, nutritional differences between different grass-fed systems and grain-fed systems are not well explored. Therefore, the present study compares the fatty acid profiles of four different Western United States beef systems including (1) steers finished in a feedyard (120 days; CON), (2) steers grass-fed for 20 months (GF20), (3) steers grass-fed for 20 months with a 45-day grain finish (45GR), and (4) steers grass-fed for 25 months (GF25). Longissimus thoracis serving of n-3 PUFA was lowest for CON compared to all other treatments (P < 0.05). No difference in eicosapentaenoic acid or docosapentaenoic acid was observed between 45GR, GF20, and GF25 (P > 0.05). Grass-fed treatments resulted in t10-18:1:t11-18-1 ratios 15 to 24 times lower compared to CON (P < 0.05). Grass- and grain-finishing resulted in nutritional trade-offs rather than nutritional absolutes with GF25 and 45GR resulting in a more favorable fatty acid profile than GF20.