Can endophyte-infected tall fescue minimize the grass tetany risk?

Non-toxic Neotyphodium (novel endophyte) has been shown to provide similar agronomic performance as wild-type endophyte to deter pathogens without exerting adverse effects on livestock. While the grass/novel endophyte interaction does not synthesize alkaloid peramine that has been linked to mammal toxicity, the connection between wild (naturally occurring) and/or novel endophyte infection and tetany ratio in forage has not been evaluated. The risk of grass tetany was evaluated in naturally occurring endophyte-infected tall fescue grass grown in Japanese Andisol. Three tall fescue (Festuca arundinacea Schreb.) ecotypes (Fukaura, Koiwai and Showa) either infected with Neotyphodium coenophialum (Morgan-Jones and Gams) Glenn, Bacon and Hanlin (E+), or noninfected (E-) were grown in low phosphorus (P) availability black Andisol and high P availability red Andisol under a controlled environment. The biomass nutrient concentration was measured and the tetany ratio, K/(Ca+Mg), was established for all three fescue ecotypes. Results showed that K, Ca, and Mg concentrations and the K/(Ca+Mg) were significantly affected by endophytes, soils, and ecotypes and their interactions. Regardless of ecotypes and soils, K, Ca, and Mg concentrations were higher in endophyte-infected plants when compared to the control. Among the endophyte-infected ecotypes, the Fukaura and Koiwai showed higher K, Ca, and Mg concentrations in red Andisol. In contrast, the Showa ecotype showed higher K, Ca, and Mg concentrations in endophyte-infected plants than the control in black Andisol. Notwithstanding ecotypes and soils, endophyte-infected plants showed lower K/(Ca+Mg) than their counterparts, suggesting that the grass/endophyte interaction could provide a means of reducing the incidence of grass tetany in livestock.