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¶ Introduction
Fungi that grow in grains and forage can produce poisonous “mycotoxins”. These compounds may affect both human and livestock health. Only a small number of mycotoxins are of concern to livestock, even though more than four hundred individual mycotoxins have been identified.
¶ A. What is “ergot”?
- Complex group of mycotoxins produced by metabolism of Claviceps pupurea and related fungi.
- Are in class of compounds called “alkaloids”
- Group of naturally occurring chemical compounds that mostly contain basic nitrogen atoms
- Well‐known alkaloids include morphine, strychnine, quinine, ephedrine, and nicotine
- Are in class of compounds called “alkaloids”
- C. purpurea infects nearly all grasses used for hay and haylage
- Barley, rye, wheat
- Alkaloids in infected rye grain used for bread
- Toxicity symptoms may have been source of historical witch hysteria
- e.g., 1692 Salem (Massachusetts) Witch Trial
- Brome, fescue, bluegrass, timothy, Western and intermediate wheatgrass and other grasses
- Quackgrass, dallisgrass
- Barley, rye, wheat
¶ B. Advisory levels
- U.S. Food and Drug Administration (FDA) has not set action, advisory, or guidance levels
- May cause poisoning symptoms in cattle: 0.1% to 0.3% contamination
- Grain may be graded as “ergoty”
- Wheat or durum: 0.05% by weight
- Barley, oats, triticale: 0.1% by weight
- Rye: 0.3% by weight
- Ergot sclerotia may fragment during harvest or processing
- Requires microscopic examination to detect in feeds or grain products
¶ C. Conditions favoring contamination
- Favored by cool damp conditions at flowering
- Fungus infects through the flower
- Forms sclerotia called “ergot”
- sclerotia: compact mass of hardened fungal mycelium containing food reserves
- Is dormant; able to survive for relatively long time
- Only forms in seed head
- Forms in original location of seed formation
- Similar in shape to the grain (see Figure 1)
- Usually slightly to significantly larger
- Hard; colored dark purple or black (see Figure 2)
¶ Figure 1. Ergot Sclerotia Protruding From Rye Heads
¶ Figure 2. Ergot-Contaminated Wheat Grain
¶ D. Health effects
- Called “ergotism”
- May affect cattle, sheep, swine, horses
- Rough hair coat
- Staggers
- Nervous and motor disorders
- Lameness
- Insufficient blood flow to the extremities
- Tissue necrosis >> “dry gangrene”
- May stand in water for extended time
- May result in loss of ears, tail, feet or hooves
- Ears and tail affected first
- Additional effects to swine
- Possible infertility
- Lactation failure
¶ E. Managing ergot
- No practical way to eliminate ergot in pasture
- Must examine pasture and hay for ergot
- Infection depends on climatic conditions
- Fescue endophyte toxins similar to ergot toxins
- Sclerotia only forms in seed head
- Graze infected pasture before seed head develops
- Clip grass with seed head before grazing
- Remove access to infected feedstuffs immediately when symptoms are observed
¶ References
Adams, R.S. et.al. Mold and mycotoxin problems in livestock feeding. DAS 93‐21. Pennsylvania State Univ. Coop. Ext. Svc. 17 pg. http://www.das.psu.edu/research‐extension/dairy/nutrition/pdf/ mold.pdf/view?searchterm=mycotoxin [accessed 01Nov2009]
Randle, R. and D. Griffin. August 2013. Ergot Poisoning in Cattle. Univ. of Nebraska Extension. http://beef.unl.edu/cattleproduction/ergotpoisoning‐in‐cattle [accessed 18Sep2017]
Wegulo, S. and M. Carlson. Ergot of Small Grain Cereals and Grasses and its Health Effects on Humans and Livestock. Pub. EC1880. Univ. of Nebr. Ext. http://extensionpublications.unl.edu/assets/pdf/ec1880.pdf [accessed 18Sept2017]
Kuldau G.A. (2008). Managing mycotoxins in Northeast silages. http://www.das.psu.edu/dairynutr‐ition/docum‐ents/kuldau.pdf [accessed 18Sep2017]