Activities and Effects of Ergot Alkaloids on Livestock Physiology and Production

Abstract

Consumption of feedstuffs contaminated with ergot alkaloids has a broad impact on many different physiological mechanisms that alters the homeostasis of livestock. This change in homeostasis causes an increased sensitivity in livestock to perturbations in the ambient environment, resulting in an increased sensitivity to such stressors. This ultimately results in large financial losses in the form of production losses to livestock producers around the world. This review will focus on the underlying physiological mechanisms that are affected by ergot alkaloids that lead to decreases in livestock production.

Ergot Alkaloids of the Family Clavicipitaceae

“…Epichloë species, which grow endobiotically and are often seed-transmitted in cool-season grasses (Poaceae, subfamily Poöideae), can be a source of various ergot alkaloids that cause important toxic syndromes in livestock (Chen et al 2015; Klotz 2015; Shymanovich et al 2015; Thompson and Stuedemann 1993). Periglandula species, which are epibiotic symbionts on buds and leaf surfaces of morning glories (Convolvulaceae, tribe Ipomoeae), produce diverse ergot alkaloids (Beaulieu et al 2015).…”

“…Indole-diterpenes, such as lolitrem B, are responsible for tremors experienced by sheep and other grazing mammals (di Menna et al 2012), whereas the ergot alkaloids cause symptoms that can vary depending the particular alkaloids and condition of the animal, such as heat or cold temperature stress (Klotz 2015; Spiers et al 1995). Some symptoms of ergot-alkaloid toxicity in grazing livestock include elevated body temperature, reduced lactation, reduced fertility, vasoconstriction, and dry gangrene with loss of hooves (Burke et al 2001; Gadberry et al 2003; Klotz 2015; Thompson and Stuedemann 1993). Though they can have detrimental effects on livestock, the endophytes can be vital for the persistence of grass stands (Malinowski and Belesky 2000; Schardl et al 2004).…”

“…The most intensively studied systems have been Epichloë coenophiala in tall fescue ( Lolium arundinaceum = Schedonorus arundinaceus ), which can cause ergot-alkaloid poisoning (Klotz 2015), and Epichloë festucae var. lolii in perennial ryegrass ( Lolium perenne ), which can cause tremors or staggers attributable to lolitrems (a group of indole-diterpenes) (di Menna et al 2012).…”

The occurrence of ryegrass staggers and heat stress in sheep grazing ryegrass-endophyte associations with diverse alkaloid profiles

“…In contrast, lolitrem B is the cause of ryegrass staggers and has some minor effects on Argentine stem weevil (Fletcher and Harvey 1981;Fletcher 1982;di Menna et al 2012). Ergovaline causes heat stress (Klotz 2015), as well as giving ryegrass protection against black beetle (Heteronychus arator) (Ball et al 1997;Popay and Hume 2011). Due to the beneficial effects of endophytes, the cultivation of endophyte-free ryegrass for permanent pastures is not a costeffective option under most farming conditions in Australia and New Zealand due to poor productivity and persistence of the ryegrass component (Hume and Sewell 2014;Thom et al 2014).…”

Fescue toxicosis and its influence on the rumen microbiome: mitigation of production losses through clover isoflavones

“…Klotz (2015) described several levels of ergot alkaloids consumed and the effect of each dose, with 0.009 mg/kg BW ergovaline resulting in symptoms of fescue foot, and higher doses of 0.016 mg/kg BW resulting in inflammation of the hoof. Nicol and Klotz (2016) further described a maximum ergovaline concentration of typical ryegrass pastures in New Zealand at 0.7 mg/kg DM, considered significantly higher than allowed concentrations in the United States.…”