HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Hemken, R. W. Articles by Bush, L. P. Search for Related Content PubMed PubMed Citation Articles by Hemken, R. W. Articles by Bush, L. P.

Interaction of Environmental Temperature and Anti-Quality Factors on the Severity of Summer Fescue Toxicosis¹

University of Kentucky^,5, Lexington, 40546

Abstract

Two experimental strains of tall fescue grass (Festuca arundinacea Schreb) that had previously been shown to produce differences in animal performance during the summer period were fed to Holstein calves in temperature controlled rooms. In the first year, GI-306 (less toxic) and GI-307 (more toxic) tall fescues were fed during July in rooms maintained at 10 to 13, 21 to 23 and 34 to 35 C. In the second year, the same tall fescues and orchardgrass were fed at a high temperature during May (32 to 33 C), July (34 to 35 C) and October (31 to 32 C). A comparison at a lower temperature (16 to 18 C) was also included in the July and October trials. In both years, calves consuming GI-307 tall fescue consistently had lower dry matter intakes, higher rectal temperatures, higher respiration rates and lower weight gains than those fed GI-306 tall fescue or orchard-grass at temperatures above 31 C. At lower ambient temperatures, differences in dry matter intake, rectal temperature and respiration rates between animals on the two strains of forage were not statistically different. The results demonstrate the poor performance of cattle grazing fescue is related to environmental temperature and that the toxic substance(s) is present throughout the growing season.

¹ This manuscript (80-5-3-73) is published with the approval of the Director of the Kentucky Agr. Exp. Sta.

² Present address: Dept. of Anim. and Vet. Sci., Univ. of Maine, Orono 00473.

³ Dept. of Agron. and USDA-SEA-AR, Lexington, KY.

⁴ Dept. of Agron.

⁵ Dept. of Anim. Sci.