Cattle Losses, Tall Larkspur, and Their Control

Abstract

Correlation analyses of records of cattle poisoned by tall larkspur (Delphinium barbeyi Huth.) on three similar and adjacent cattle allotments on the Wasatch Plateau produced low r2, indicating that losses are not related to annual fluctuations in environmental conditions or other factors shared by all three allotments. Control of the large, dense patches of tall larkspur with herbicides in one 2,000 acre subalpine pasture on the Manti Canyon Cattle Allotment dramatically reduced cattle losses. Small patches and scattered plants, which are difficult to locate and laborious to treat, apparently contribute very little to cattle losses. Examination of ruminal contents of calves found dead in the subalpine pasture in a 2-year period revealed large quantities of tall larkspur. None of the calves were orphans. All evidence suggests that the calves dying in the subalpine pastures were poisoned by tall larkspur. While mature cattle ingest lethal levels of tall larkspur in the large, dense patches, calves are apparently intoxicated by ingesting tall larkspur growing in small patches in the groves of trees scattered over the subalpine grazing units.