Date of Graduation

Fall 2013

Degree

Master of Natural and Applied Science in Agriculture

Department

College of Agriculture

Committee Chair

Gary Webb

Abstract

The aim of the current study was to examine the effects of ergot alkaloids on recovery of eleven Quarter Horses subjected to a standardized exercise test (SET) designed to mimic a trail ride. For treatment purposes, horses were paired based on disposition, age and familial relation. One horse from each pair was randomly assigned to a diet, either containing (TRT) or free (CON) of ergot alkaloids for P1, and the opposite for P2. To mimic fescue toxicosis horses were fed fescue seed cleanings that contained 175,000 ppb ergotamine and ergosine combined. Analysis of urine for ergot alkaloids confirmed levels high enough to elicit toxicosis. Horses were exercised 5 d/wk and subjected to four SET (1/horse/wk), in the third and fourth wk of each period. Each SET consisted of a warm up in an indoor arena followed by an outdoor trail ride covering 4,875 m at the jog (2.1 m/s) and extended jog (3.9 m/s). Variables measured before, during and after the SET included rectal temperature (RT), heart rate (HR), respiration rate (RR), packed cell volume (PCV), blood lactate (BL), percent weight carried (%C), sweat production (SP) and skin temperature (ST) at the poll (STP), exterior forearm (STF) and inner gaskin (STG). A composite of temperatures were recorded during the SET and recovery. Regression analysis showed no effect of speed at the jog or extended trot on HR during the SET. Horses on TRT had lower HR (p<.05) at 8 of 12 observation points during the SET. Ergot alkaloids consumption did not affect recovery HR, RR RT or ST at any time point. Results of the current study indicate that ergot alkaloids may affect the horse's ability to perform during outdoor exercise and recover during hot humid conditions.

Keywords

fescue, ergot alkaloids, ergotamine, ergosine, exercise physiology, horse

Subject Categories

Agriculture

Copyright

© Lindy Froman Christofides

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