Grass fungus could cause $1 billion in annual losses

CLEMSON UNIVERSITY EXTENSION
CLEMSON – Tall fescue is a popular grass used for grazing, hay and erosion control in the eastern United States, but one Clemson University expert believes this grass could be responsible for more than $1 billion per year in livestock production losses.

Tall fescue is a perennial bunch-type grass that grows rapidly during spring and fall. The majority of tall fescue plants contain a fungus that creates compounds which are beneficial to the plants, but toxic to livestock. The compounds created by the fungus are called “ergot alkaloids.” Susan Duckett, a professor of animal and veterinary sciences, and some of her students are conducting a study on the impact of these compounds on fetal development and postnatal growth of livestock that graze on tall fescue.

“Our hypothesis is that exposure to ergot alkaloids during pregnancy reduces fetal growth and subsequent postnatal growth of the offspring,” Duckett said. “Our study focuses on determining when exposure to these compounds is most critical to fetal growth and development.”

Toxins that result from the compounds created by the fungus create several problems for grazing animals, including low-to-no weight gain and loss of weight, as well as reproduction problems such as low conception rates and poor offspring survival.

Results of the Clemson study will be used to develop alternative management strategies for livestock beef cattle, sheep, goats and other small ruminant animals.

Jessica Britt is one animal and veterinary sciences student assisting Duckett with the study.

“The reason people really love to plant tall fescue is because of its overall hardiness and its drought resistance,” said Britt, a doctoral student from Taylors. “The characteristics that we love about fescue are because of the fungus that is in the plant. So we need that fungus to get the fescue that is hardy and drought-tolerant. But, again, the fungus that grows within the fescue plant is what produces the ergot alkaloid and that is what causes problems in these animals.”

According to Britt, researchers are trying to determine if there are certain periods of gestation when exposure to ergot alkaloids are more crucial.

“We are interested in determining if there are time periods during gestation which are more crucial to fescue toxicosis and, if so, can we mitigate these problems during those time points,” Britt said.

The fungus being studied is a common occurrence in tall fescue. Britt said that unless producers have gone in and completely replanted fields with non-toxic tall fescue, their livestock most likely are grazing tall fescue infected with the fungus.

“In the Southeast, in general, a large number of people have toxic tall fescue in their fields,” Britt said. “(Fescue toxicosis) has the potential to be a very widespread problem.”

In addition to replanting fields with non-toxic tall fescue, which can be expensive, another way to deal with the fungus is to remove all animals from infected pastures during critical time periods, Britt said.

Interest in raising beef cattle is increasing. According to a report from the United States Department of Agriculture’s (USDA) National Agricultural Statistics Service, 340,000 head of beef cattle were raised in the state in 2016, a 1.5 percent increase from 2015. The report also shows 30.3 million beef cows were raised in the entire United States as of Jan. 1. This was an increase of 4 percent from 2015.

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This material is based upon work supported by the USDA Research, Education and Economics Information System (REES) under Grant Number 2015-67015-23218. Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the USDA-REES.