Grazing behavior and forage preference of sheep with chronic locoweed toxicosis suggest no addiction.

Ralphs, M.H.
Panter, K.E.
James, L.F.
Rangeland Ecology & Management / Journal of Range Management Archives
Publication Year: 
Addiction is commonly cited as a clinical sign of locoweed (Astragalus spp. and Oxytropis spp.) poisoning. In a previous study, ewes progressively poisoned on locoweed ("locoed") in cafeteria trials did not become addicted to locoweed. Following a year of recovery, these ewes were allowed to graze locoweed-infested rangeland to determine if there was any residual preference for, or addiction to, locoweed. Neither the locoed nor control ewes consumed appreciable amounts of locoweed on rangeland where associated forage was succulent and actively growing, and where grazing pressure was sufficiently low to allow selective grazing. There was no residual preference for locoweed in previously locoed ewes. However, locoed ewes often exhibited sudden involuntary seizures when attempting to take a bite of forage. The head would tremble and tuck up under the brisket in a bobbing motion, and eye lids fluttered for a few seconds before the animal was able to proceed in feeding. Biting rate of locoed ewes was about a third less than that of the control ewes (P
Document Type: 
Journal Issue/Article
Society for Range Management

Rangeland Ecology & Management (formerly the Journal of Range Management) serves as a forum for the presentation and discussion of facts, ideas, and philosophies pertaining to the study, management, ecology, and use of rangelands and their resources. The journal is peer-reviewed and provides international exchange of scholarly research and information among persons interested in rangelands. The Global Rangelands collection includes REM content up to 5 years from the current year. More recent content is available by subscription from BioOne and the Society for Range Management, and may be available at your local university library.
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