by Jordan Strickler, University of Kentucky

The University of Kentucky (UK) Martin-Gatton College of Agriculture, Food and Environment (CAFE) has been awarded a $300,000 grant to explore the potential of 5-hydroxytryptophan (5-HTP) in mitigating fescue toxicosis in beef cattle. The research project, spearheaded by UK Department of Animal and Food Sciences assistant professor Ronald Trotta, aims to address this pervasive issue affecting beef production, especially in regions dominated by endophyte-infected tall fescue.

Fescue toxicosis reduces the weaning weight of 9 million U.S. beef calves per year by an average of 50 pounds each.

According to Trotta, the study addresses a $2 billion issue. Fescue toxicosis reduces the weaning weight of 9 million U.S. beef calves per year by an average of 50 pounds (lb.) each.

Fescue toxicosis is primarily caused by ergot alkaloids — a group of compounds derived from the fungus Epichloë coenophiala — in tall fescue and presents many problems for cattle. These include reduced feed intake, increased vasoconstriction and susceptibility to heat stress, and compromised gut integrity. This condition is especially relevant in the Bluegrass State, the leading beef cattle-producing state east of the Mississippi River, where 34.5 million acres are covered with this type of fescue.

“We will be focusing on the three primary fescue toxicosis symptoms,” Trotta explained. “The ergot alkaloids in fescue bind to specific receptors in blood vessels, causing vasoconstriction. This reduces blood flow to critical areas like the gut, decreasing nutrient absorption and activating the immune system.”

The grant will support a two-year study to evaluate the effectiveness of 5-HTP, a precursor to serotonin, in alleviating these symptoms. Increased serotonin bioavailability is expected to relax blood vessels, improve dry-matter intake and reduce immune system activation, thereby counteracting the adverse effects of ergot alkaloids.

The study will employ a multifaceted approach, integrating nutritional, hormonal and transcriptomic analyses. The researchers will examine gene expression in various body parts to understand how 5-HTP influences feed intake, vasoconstriction and gut health.

Trotta, who recently joined Martin-Gatton CAFE, expressed enthusiasm about this research’s potential effect.

“We are conducting this study under very controlled conditions, using six animals per treatment group. This smaller scale allows for precise monitoring and comprehensive data collection,” says Trotta. “This project could offer a novel and effective strategy to mitigate the clinical symptoms of fescue toxicosis, significantly benefiting beef producers in Kentucky and beyond.”

The research outcomes are expected to provide new insights into the molecular mechanisms of fescue toxicosis and the therapeutic potential of 5-HTP, contributing to improved animal health and agricultural productivity.

Editor’s note: Jordan Strickler is an agriculture communications specialist with the University of Kentucky. This material is based upon work that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, under award number 2024-67016-42707. Any opinions, findings, conclusions or recommendations expressed in this publication are those of the author(s) and should not be construed to represent any official USDA or U.S. Government determination or policy. [Lead photo by Steve Patton.]

Angus Beef Bulletin EXTRA, Vol. 16, No. 9-B