Stock grazing on pastures in which Phalaris species are the predominant grass have on occasion developed what appears to be a neurological disorder which results in the “staggers,” a term used to describe their unsteady, stumbling gait. Other manifestations include restlessness, hyperexcitability, twitching of the ears, head bobbing, jaw tremors, heavy breathing, and an excessively high pulse rate. When driven, the animals are often unable to unflex their forelimbs and they collapse. The pathological features associated with the disorder have not been well defined, although some degeneration of tracts in the spinal cord and haemosiderosis of the kidney have often been observed. Heavy losses of animals have occurred.

Excellent technical assistance was provided by Peggy Adams and Mary Miller. The assistance of Joh Mitchell, Don Torell, and the Humboldt County Wool Growers in conducting the field studies and of J. E. Street in obtaining seed for the greenhouse studies is gratefully acknow ledged. The study was partially funded by grants from the U. S. Public Health Service and the Kearney Foundation.