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ARS Home » Midwest Area » Lexington, Kentucky » Forage-animal Production Research » Research » Publications at this Location » Publication #267946
Title: Ergovaline recovery from digested residues of grazed tall fescue seedheads

Author
item GOFF, BEN - University Of Kentucky
item Aiken, Glen
item WITT, BILL - University Of Kentucky

Submitted to: American Forage and Grassland Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/26/2011
Publication Date: 6/12/2011
Citation: Goff, B.M., Aiken, G.E., Witt, B.W. 2011. Ergovaline recovery from digested residues of grazed tall fescue seedheads. In: American Forage and Grassland Conference Proceedings, Jun e 12-15, 2011, Frenchlick, IN. 2011 CDROM.

Interpretive Summary: Ergot alkaloids produced by the endophyte [Neotyphodium coenophialum] of tall fescue [Lolium arundinaceum] induce a toxicosis in cattle that is a common problem in the southeastern USA. While these toxins are heavily concentrated within the seedheads, there is a lack of information on the degree that ergot alkaloids are released during digestion. The objectives of this study were to determine the extent at which cattle grazed seedheads from tall fescue pastures to determine the amount of ergovaline that may be released into the rumen. Seedheads were collected from pastures being grazed with Angus-cross steers from early-May until mid-June. Also, pastures were monitored for the grazing of seedheads by the cattle. Samples were digested with two-stage acid-pepsin procedure and the residues, as well as undigested materials, were tested for ergovaline content. Cattle did not graze the seedheads until the first week of June, and within two weeks approximately 80% of the seedheads within the field showed evidence of biting. The in vitro organic matter digestibility (IVOMD) and ergovaline concentration of the seedheads increased through the growing season. The percentage of ergovaline released decreased with more mature seedheads; however, this decrease was small and more total ergovaline was potentially released into the animal was greater for these samples. Results of the experiment indicated that minimum of 96% of the ergovaline contained within tall fescue seedheads is potentially released during digestion, and that management strategies should be aimed at controlling reproductive growth of the grass.

Technical Abstract: Ergot alkaloids produced by the endophyte [Neotyphodium coenophialum] of tall fescue [Lolium arundinaceum] induce a toxicosis in cattle that is a common problem in the southeastern USA. While these toxins are heavily concentrated within the seedheads, there is a lack of information on the degree that ergot alkaloids are released during digestion. The objectives of this study were to determine the extent at which cattle grazed seedheads from tall fescue pastures to determine the amount of ergovaline that may be released into the rumen. Seedheads were collected from pastures being grazed with Angus-cross steers from early-May until mid-June. Also, pastures were monitored for the grazing of seedheads by the cattle. Samples were digested with two-stage acid-pepsin procedure and the residues, as well as undigested materials, were tested for ergovaline content. Cattle did not graze the seedheads until the first week of June, and within two weeks approximately 80% of the seedheads within the field showed evidence of biting. The in vitro organic matter digestibility (IVOMD) and ergovaline concentration of the seedheads increased through the growing season. The percentage of ergovaline released decreased with more mature seedheads; however, this decrease was small and more total ergovaline was potentially released into the animal was greater for these samples. Results of the experiment indicated that minimum of 96% of the ergovaline contained within tall fescue seedheads is potentially released during digestion, and that management strategies should be aimed at controlling reproductive growth of the grass.