The aetiology of phalaris straggers in sheep. III. The preventive effect of various oral dose rates of cobalt

Abstract

The earlier finding that cobalt administered orally in adequate amounts completely prevents phalaris staggers from developing in sheep that graze pastures containing a preponderance of Phalaris tuberosa L. has been confirmed. Weekly doses of 7 mg cobalt did not always afford protection but supplements of 28 mg (or more) at weekly (or more frequent) intervals were invariably effective. Extremely small supplements (0.05 mg) were effective when administered twice daily, but when the interval between doses was 4 weeks even very large amounts (280 mg) did not prevent staggers. The principles that govern the preventive administration of cobalt are discussed and relevant analytical data are presented.