Loline Alkaloids in Tall Fescue Hay and Seed and Their Relationship to Summer Fescue Toxicosis in Cattle

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Abstract
In 3 trials, young Holstein steers housed in restraint type crates in a controlled environment room were fed tall fescue hay or seed diets to determine the ability of the diets to produce signs of summer syndrome. Trial 1 examined the effects of dehydration and extended storage of G1-307 fescue compared to alfalfa on dairy steers. Calves fed G1-307 fescue had lower daily feed intake, higher rectal temperatures and respiration rates, and lost 13.4 kg more body weight during the experimental period as compared to those fed alfalfa hay. In trial 2, benomyl (a systemic fungicide) was used to eliminate the fungus Epichloe typhina from treated G1-307 fescue plants. Steers fed the treated G1-307 fescue progeny had higher daily intakes, lower rectal temperature, lower respiration rates, and lost less body wieght over the trial period as compared with those fed untreated G1-307 fescue. Kenhy tall fescue seeds with and without analyzable N-acetyl and N-formyl loline alkaloids and a control diet were fed in trial 3. Steers fed the seed with the loline alkaloids had reduced intake, higher rectal temperatures, and lost 10.9 kg more body weight over the trial period than steers fed seed that did not contain loline alkaloids.