|Oliver, Christy - NORTH DAKOTA STATE UNIV|
|Anderson, Robin - ARS COLLEGE STATION TX|
|Caton, Joel - NORTH DAKOTA STATE UNIV|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 8, 2005
Publication Date: March 1, 2005
Citation: Oliver, C.E., Smith, D.J., Anderson, R.C., Caton, J.S. 2005. Pharmacokinetics of intraruminally-dosed 36cl-labeled sodium chlorate in cattle. [abstract] American Chemical Society (ACS) Spring Meetings. March 14-17, 2005, San Diego, CA, Picogram No. 68, Abstract No. 105. Technical Abstract: Six ruminally cannulated Loala cattle (3 steers, 3 heifers; 151 plus or minus 36 kg) received 1 of 3 sodium chlorate levels (21, 42, or 63 mg/kg BW) in 4 intraruminal boluses over 24 hours. Blood and serum were collected by jugular catheter at h 0, 0.5, 1, 2, 4, 6, 8, 8.5, 9, 10, 12, 14, 16, 16.5, 17, 18, 20, 22, 24, 24.5, 25, 26, 28, 30, 32, 36, 40, 44, and 48 relative to first dose. Total radioactivity of whole blood and serum was measured by liquid scintillation counting. Serum chlorate was assayed by passing diluted serum through an AgNO3 column to precipitate chloride; chlorate content of eluent was determined by liquid scintillation counting. Peak total radioactivity occurred between h 30 and 36 and was dose dependent in whole blood (low: 48 ppm; medium: 83 ppm; high: 97 ppm) and serum (low: 54 ppm; medium: 99 ppm; high: 118 ppm); higher serum radioactivity concentrations indicate that chlorate/chloride do not concentrate in the blood cell fraction. Serum chlorate peaked between 1 to 2 hours post dosing and then returned to baseline between dosing times in all but the high dose. Peak serum chlorate levels were dose dependent (low: 5.6 ppm; medium: 12.0 ppm; high: 20.5 ppm). Half-lives of chlorate absorption (0.5 to 1 h) and elimination (4 to 6 h) were estimated. Chlorate is rapidly eliminated from the circulation, but chloride concentrates in blood. Intraruminally-dosed chlorate is rapidly absorbed, mostly as chloride; the chlorate fraction is quickly eliminated from blood.