Fescue toxicosis

Bovine Abortifacient and Teratogenic Toxins

“…Chemical analysis via thin-layer chromatography, gas and high performance liquid chromatography, and mass spectrometry can accurately detect the concentrations of various mycotoxins in properly collected and prepared samples. 41,42 Ergot alkaloids Ergot alkaloids include more than 80 indole compounds and are associated with two mycotoxicoses in livestock species: fescue toxicosis and ergotism. 2 Both conditions may share similar clinical manifestations and in many cases may be indistinguishable from one another.…”

“…Fescue toxicosis is a descriptive term used for several clinical syndromes (summer slump, fescue foot, and fat necrosis) attributed to ingestion of endophyteinfected tall fescue. 42 Tall fescue (L. arundinaceum [Shreb]) is a cool-season perennial grass grown in temperate climates and is one of the most abundant forage crops in the continental United States. 46 In cases of fescue toxicosis, livestock ingest the fungal endophyte Neotyphodium coenophialum (formerly Acremonium coenophialum and Epichloe typhina) that grows within the intercellular spaces of the leaf sheaths, stems, and seeds of tall fescue grass.…”

“…The endophyte produces toxins (ergot alkaloids, loline alkaloids, and peramine) that are distributed throughout the plant making it more resistant to drought, parasitism, and fungal infection. 42 The endophyte of tall fescue produces an array of ergot alkaloids but ergovaline is the primary ergopeptine alkaloid believed to be responsible for inducing toxicosis. Ergot alkaloids are highly concentrated within the seeds of tall fescue and levels are greatest in the summer and early fall when seed heads are present.…”

“…46 Drought and rainy conditions as well as fertilization with nitrogen-and phosphorus-based fertilizers tend to increase ergovaline concentrations. 42 Several syndromes including summer slump, fescue foot ( Figure 65.7), and fat necrosis (lipomatosis) are associated with fescue toxicosis in cattle. The most costly of the three is summer slump.…”

“…As the name implies clinical manifestations of this condition are most often appreciated in summer months when the ambient temperature is above 31 °C. 42 Affected cattle typically have a rough hair coat, unthrifty appearance, reduced feed intake, decreased milk production with lower weaning weights of calves, reduced conception rates, agitation/nervousness, ptyalism, and increased respiratory rates. 42,47 …”