The Effects of Endophyte-Infected Tall Fescue on the Production and Reproductive Performance Parameters of Beef Cattle and Calves

Abstract

Records from 2012 to 2019 for two herds were analyzed to determine how tall fescue (<i>Schedonorus arundinaceus</i> (Schreb.) Dumont) endophyte (<i>Epichlo&euml; coenophialum</i>) status affected the productivity of spring-calving cows and calves. Pastures either contained tall fescue with wildtype endophyte (high levels of ergot alkaloids) or novel- or endophyte-free tall fescue (largely ergot alkaloid free). The experimental design was a randomized complete block with year as the replication unit. Forage samples from the farm with toxic endophyte-infected tall fescue contained 1136 &plusmn; 413 ppb total ergot alkaloids, while forage from the non-toxic pastures on the second farm contained 118 &plusmn; 83 ppb total ergot alkaloids. Artificial insemination pregnancy rates and calving rates were greater (<i>p</i> &lt; 0.05) for cows that grazed non-toxic tall fescue (51.2 &plusmn; 2.8% and 93.5 &plusmn; 1.4%, respectively) than for cows on toxic endophyte-infected tall fescue (43.3 &plusmn; 2.8% and 88.8 &plusmn; 1.4%, respectively). Birth weights and weaning weights were greater (<i>p</i> &lt; 0.05) for calves from the non-toxic tall fescue system (37 &plusmn; 1 kg and 278 &plusmn; 8 kg, respectively) than for calves from the toxic endophyte-infected tall fescue system (33 &plusmn; 1 kg and 254 &plusmn; 8 kg, respectively). Raising cattle on tall fescue without the toxic endophyte improved cow and calf productivity.