Ergopeptine Alkaloids in Grazed Tall Fescue

Abstract

Endophyte (Acremonium coenophialum Morgan-Jones et Gams) -infected tall fescue (Festuca arundinacea Scbreb.) produces ergopeptine alkaloids (EP) that may be associated with fescue toxicosis symptoms in cattle (Bos taurus). A study was conducted during 1983 and 1984 at Watkinsville, GA, to determine the effects of endophyte infection, season, and N fertilization on EP concentration and steer average daily gain (ADG) in grazed 0.7-ha tall fescue paddocks. Treatments included low (LF) and high (HF) endophyte infection frequency 'Kentucky-31' (KY-31) tall fescue fertilized with 134 or 336 kg N ha-• (2x2 factorial) replicated three times. The cultivars AU Triumph and Johnstone were also evaluated. Animals were managed using put-and-take grazing system. Ergopeptine alkaloid concentration (ergovaline was 80% of total) was greater in HF KY-31 than LF KY-31 in both years. Peak ergovaline concentrations occurred in spring and again in autumn (1984) when concentrations in HF KY-31 approached 1 mk kg-•. Mid-summer concentrations were about one-third the autumn maximum for HF and LF KY-31. Nitrogen fertilization bad minimal effect on ergovaline concentration in the spring-summer of 1983 but increased concentrations in LF KY-31 in 1984. Ergopeptine alkaloids were not detected in endophyte-free AU Triumph, and were detected in low amounts ( < 0.1 mg kg-1 ) in a pre-varietal release of Johnstone containing 7 to 10% endophyte. Increased ergovaline was associated with decreased ADG in the spring-summer of 1983 and 1984; however, there was no significant association between ergovaline and ADG when the entire (April-December) 1984 growing season was considered, suggesting that ergopeptine alkaloids may operate in conjunction with other environmental and nutritional factors to elicit fescue toxicosis symptoms.

Endophyte Infection of Tall Fescue and the Impact of Climatic Factors on Ergovaline Concentrations in Field Crops Cultivated in Southern France

“…20 The fall peak corresponded to plant regrowth ("regain"), at the same time as an increase in ergovaline production in planta, and has been previously reported. 21 By contrast, the winter peak is probably linked to the accumulation of ergovaline in the plant that occurs during senescence. High ergovaline has already been reported in leaves in winter.…”

Effect of Neotyphodium Uncinatum Endophyte on Meadow Fescue Yielding, Health Status and Ergovaline Production in Host-Plants

“…As far as weather conditions are concerned, higher amounts of alkaloids are usually observed late in spring and early autumn. Higher nitrogen fertilisation also enhances an increase in the content of ergopeptine alkaloids in grasses (Lyons et al 1990;Belesky et al 1988). A three-fold increase in the nitrogen dose can increase the content of alkaloids by 60-80% in tall fescue, depending on the year.…”

Soil-profile distribution of inorganic N during 6 years of integrated crop-livestock management

“…S.J. Darbyshire] pastures, varying in tall fescue-endophyte association and fertilization level (Belesky et al, 1988). Pastures were grazed with Angus cattle each year, primarily in spring and autumn.…”