RESEARCH PROJECTS

Fescue Toxicosis

Tall fescue (Lolium arundinaceum (Schreb.)) is a cool season grass and grows extensively throughout the United States.  Approximately 75% of tall fescue is infected by the endophyte Neotyphodium coenophialum, resulting in the presence of ergot alkaloids (see http://www.ca.uky.edu/agc/pubs/agr/agr175/tall.htm for a photograph and description of tall fescue). 

Ergot alkaloids disrupt reproductive function in cattle and horses, particularly in late pregnancy where fescue toxicosis is characterized by poor pregnancy outcome (horses: prolonged pregnancy, agalactia, thickened placentas, dysmature foals and in extreme cases, foal and mare mortality).  The effect of ergot alkaloids on early embryonic and fetal development and survival has received much less attention and among published studies there are conflicting results. 

A primary focus of current research is the effect of consuming endophyte infected tall fescue during early pregnancy. The mechanisms whereby fescue toxicosis might lead to reproductive dysfunction during early pregnancy are not completely understood.  Several pathways might be proposed, however, since it is known that ergot alkaloids are potent vasoconstrictors and thus fetal death and resorption may simply reflect inadequate nutrient supply. 

An alternative or additional mechanism might be that exposure to ergot alkaloids leads to increased circulating concentrations of pro-inflammatory cytokines.  In humans, activation of the immune system and an increase in circulating inflammatory cytokines leads to ovarian insufficiency and early pregnancy loss via decreased secretion of progesterone from the corpus luteum.  In cattle and mice, exposure to ergot alkaloids also is associated with increased circulating concentrations of inflammatory cytokines and it has been suggested that inflammatory cytokines might play a role in fescue toxicosis. 

The goal of this research project, therefore, is to determine changes in several pro-inflammatory cytokines during early pregnancy in mares consuming endophyte infected tall fescue grass.