Animal performance, carcass quality and economics of cattle finished after grazing endophyte-infected, endophyte-free or nonergot alkaloid-producing endophyte-infected tall fescue

Angus-cross steers grazed wild type endophyte-infected (E+), nonergot alkaloid-producing endophyte-infected (AR542), or endophyte-free (E-) tall fescue pastures at two locations. Twenty-four animals per location were transported to a research feedlot after the completion of the grazing phase and fed for 100 d. Grazing average daily gain (ADG) was 0.47 kg/d greater (P=0.001) for cattle grazing AR542 than those grazing E+ pastures. In the feedlot, overall ADG did not differ among AR542 and E+ (P=0.40) or AR542 and E- (P=0.19), and averaged 2.09 + 0.15 kg/d across all treatments. Feed efficiency was greater (P=0.02) for E+ than AR542. Hot carcass weight was 40 kg greater (P=0.01) for AR542 than E+. Other carcass traits did not differ (P≥0.10) among treatments. Net present values (NPV) were $177.08/ha for E- and $336.76/ha for AR542 compared to E+. Keywords: beef, endophyte, carcass