EARLY-SEASON GRAZING BY CATTLE OF TALL LARKSPUR (DELPHINIUM SPP) INFESTED RANGELAND

A series of summer grazing studies were conducted to evaluate cattle c onsumption of preflowering tall larkspur (Delphinium barbeyi [Huth] or D, occidentale [Wats,] Wats.) on mountain rangeland in Utah, Colorado , and Idaho during 1987 to 1995, Cattle ate little or no larkspur befo re flowering racemes were elongated. Consumption of tall larkspur by c attle was also generally low during the early flower stage, with some notable exceptions at the Salina and Manti, Utah sites, These grazing studies indicate that risk of losing cattle to tall larkspur is low if plants have not flowered, Even though concentration of toxic alkaloid s is typically much higher in immature compared to mature tall Larkspu r, toxicosis is unlikely to occur because consumption by cattle is low , Many livestock operations can gain 4 to 5 weeks of low-risk grazing on tab larkspur-infested rangeland early in the grazing season, and th is should be considered in developing grazing management plans.