250 Evaluation of Green Grass as a feed ingredient in beef finishing rations and impact on cattle performance, carcass characteristics, and fatty acid profiles in meat

Abstract

Abstract A finishing study used 240 crossbred steers (initial BW=340 ±24 kg) to evaluate performance, carcass characteristics, and fatty acid profiles of beef from finishing steers. Four inclusions (0, 10, 20, 30 % DM basis) of Green Grass displaced dry rolled corn in the finishing diet. Green Grass is a blend of herbs and plants imported from Korea that are high in omega-3 fatty acids with 13.9 % fat,32.0 % CP, and 27.0 % Acid detergent fiber. The remaining diet consisted of 15 % WDGS, 20 % corn silage, and 6 % liquid supplement (DM basis). There were no differences in final BW, gain or carcass traits (P³0.14). Cattle were harvested over three slaughter days and were fed for 190, 199, or 203 days. Dry matter intake linearly increased (P = 0.04)as Green Grass inclusion increased in the diet. A linear response (P£0.01) to feeding Green Grass was observed for G:F, with steers fed Green Grass having lower feed efficiency than control cattle. The G:F of cattle fed Green Grass was 5.4, 3.4, and 6.8 % lower in G:F as inclusion increased suggesting Green Grass has 68.6 % the energy of corn it replaced. Steers fed 30 % Green Grass had a lower marbling score. Linear increases in alpha linolenic acid, trans-unsaturated fatty acids, and omega-3 fatty acids (P£0.01) were observed in steak samples from steers fed increasing inclusion of Green Grass. Including up to 30 % inclusion of Green Grass on a DM basis in finishing diets decreased G:F; however, it appeared to have no other effects on performance or carcass characteristics. Feeding Green Grass linearly improved omega-3 fatty acid concentration in beef.