Open AccessDynamics of peripheral blood flow for endophyte-naive cattle fed toxic tall fescue seed
Author(s) -
Glen E. Aiken,
B. Kirch,
J. R. Strickland
Publication year - 2007
Publication title -
grassland research and practice series
Language(s) - English
Resource type - Journals
eISSN - 2463-4751
pISSN - 0110-8581
DOI - 10.33584/rps.13.2006.3164
Subject(s) - hay , festuca arundinacea , biology , zoology , endophyte , vasoconstriction , blood flow , agronomy , botany , medicine , poaceae , endocrinology
Doppler ultrasonography was used to measure blood flow dynamics in the caudal artery of heifers that were fed diets with either endophyte-infected (E+) or non-infected (E+) tall fescue (Festuca arundinacea Schreb.) seed. Heifers were assigned to six pens and during an adjustment period were fed alfalfa hay for 5 d, and then the hay plus a concentrate with E- tall fescue seed for 9 d. An 11-d experimental period followed with three pens being changed to hay plus concentrate with E+ seed. Caudal artery area in E+ heifers had declined by 4 h from the initial feeding of the E+ diet before stabilising at the lower level between 4 and 28 h. Heart rates followed a similar trend. Blood flow rate was lower in E+ heifers from 28 h onwards. Results indicated that vasoconstriction can occur in cattle within 28 h from initial consumption of toxic fescue. Keywords: tall fescue, fescue toxicosis, cattle, vasoconstriction