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United States Department of Agriculture

Agricultural Research Service

Research Project: OPTIMIZING THE BIOLOGY OF THE ANIMAL-PLANT INTERFACE FOR IMPROVED SUSTAINABILITY OF FORAGE-BASED ANIMAL ENTERPRISES Title: Impact of the Endophyte on Animal Production

Author
item Aiken, Glen

Submitted to: American Forage and Grassland Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 24, 2010
Publication Date: June 21, 2010
Citation: Aiken, G.E. 2010. Impact of the Endophyte on Animal Production. American Forage and Grassland Conference Proceedings.

Interpretive Summary: Tall fescue is extensively utilized for cattle grazing in the upper transition zone of the USA. Production and persistence of this cool-season grass has been attributed to alkaloids produced by a fungal endophyte that infects most tall fescue plants. Unfortunately, the endophyte also produces ergot alkaloids that induce a toxicosis in cattle that causes hormonal imbalances and constriction of blood flow to peripheral tissue. Consequently, calf weight gain can be very low, particularly in warm and humid environments, which limits the use of fescue for stocker production. Ergot alkaloids cause reductions in certain hormones needed for reproduction and lactation; therefore, calving percentages, milk yields, and weaning weights on toxic tall fescue can be less than desirable. Reduction in calf numbers and weaning weights annually costs the U.S. beef industry approximately $800 million. A review paper discusses the impact of toxic endophyte-infected tall fescue on profitability of beef cattle production from nursing to finishing. Options in avoiding fescue toxicosis or reducing the severity of the malady also will be presented.

Technical Abstract: Tall fescue (Lolium arundinaceum L.) is extensively utilized as pasture forage in the upper transition zone of the USA. Its production and persistence is attributed to alkaloids produced by a fungal endophyte (Neotyphodium coenophialum) that infects most tall fescue plants. The endophyte also produces ergot alkaloids that induce a toxicosis in cattle that causes hormonal imbalances and constriction of blood flow to peripheral tissues that restrict the animal’s ability to dissipate core body heat. Consequently, calf weight gain can be very low, particularly in warm and humid environments, which limits the use of fescue for stocker production. Ergot alkaloids cause reductions in certain hormones needed for reproduction and lactation; therefore, calving percentages, milk yields, and weaning weights on toxic tall fescue can be less than desirable. Further, there is concern of carry-over effects of ergot alkaloids into the feedyard. This paper discusses the impact of toxic endophyte-infected tall fescue on profitability of beef cattle production from nursing to finishing, and presents management options in avoiding or reducing the severity of toxicosis.

Last Modified: 10/31/2014
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