Steer Performance and Association of Acremonium coenophialum Fungal Endophyte on Tall Fescue Pasture¹

Abstract

Poor animal performance on tall fescue (Festuca arundinacea Schreb.) pasture may be associated with toxic products produced by the fungal endophyte Acremonium coenophialum Morgan‐Jones and Gams (previously identified and referred to as Epichloe typhina (Fries) Tulasne). The object of this study was to determine steer performance on ‘Kentucky 31’ tall fescue pastures which were either heavily infested or relatively free of the fungal endophyte. Replicated 1.2 ha paddocks were located in west central Alabama on three soils, Sumter clay (fine silty, carbonatic, thermic Rendolic Eutrochrept), Houston clay (very fine montmorillonitic, thermic Typic Chromudert), and Eutaw clay (very fine, montmorillonitic, thermic Entic Pelluderts). They were fertilized annually with 224 kg N ha−1 and grazed with yearling steers. The grazing season during the 4‐year period averaged from 23 October to 24 December and 26 February to 16 June. Tall fescue, averaging 94% of plants fungus infested, produced 768 animal days ha−1 and produced 384 kg beef ha−1 with an average daily gain (ADG) of 0.50 kg. Tall fescue with less than 5% of plants infested produced 593 animal days ha−1 and produced 492 kg beef ha−1, with an ADG of 0.83 kg. Rectal temperatures were 0.8 °C higher and hair coats much rougher on steers which grazed fungus‐infected grass rather than grass free of the fungus. Results of the study furnish further evidence that the fungal endophyte, A. coenophialum, is associated with low performance of steers on tall fescue pasture. In the absence of the fungal endophyte, ADG of steers on tall fescue is high and similar to that on small grain pastures.

Evaluating blood perfusion of the corpus luteum in beef cows during fescue toxicosis1

“…The seed head was infected with an endophyte, originally named Epichloe typhina and presently known as Neotyphodium coenophialum, which is the cause of the problematic ergot alkaloids . Hoveland et al (1983) fed tall fescue infected with either lesser concentrations of endophyte or greater concentrations of endophyte and confirmed these findings. Three different types of alkaloids were discovered: pyrrolizidines, peramines and ergot alkaloids (Siegel et al, 1990).…”

Impact of Consuming Tall Fescue Leaves with the Endophytic Fungus, Acremonium coenophialum, on Meadow Voles

“…Consumption of large amounts of fungus-infected tall fescue (hereafter called infected fescue) can have deleterious effects on cattle, including lower food intake, lower weight gains, higher body temperatures, reduced rates of conception, and suppressed milk production (Hoveland et al, 1983;Jackson et aI., 1984;Schmidt and Osborn, 1993;Schmidt et aI., 1982). Such problems, however, usually can be avoided by proper management, thus allowing continued use of infected cultivars of tall fescue for yearround grazing pastures (Bouton et aI., 1993).…”

Effects of the Fungal Endophyte Acremonium coenophialum on Nitrogen Accumulation and Metabolism in Tall Fescue

“…Outwardly, such infections cannot be detected despite extensive intercellular growth within the plant; the fungus is not a pathogen. Initially recognized as an essential causal factor in the toxicity of tall fescue to cattle (3,4,9), infected stands of tall fescue may be enhanced in their ability to survive under stressful environments (2,5,23). Thus, the endophytic fungus has considerable agronomic and ecological significance on tall fescue.…”