PRIOR GRAZING BY SHEEP REDUCES WAXY LARKSPUR CONSUMPTION BY CATTLE - AN OBSERVATION

Sheep are more resistent to larkspur poisoning than cattle. Grazing la rkspur with sheep before cattle turn-in may reduce the threat of cattl e poisoning. Two 2.1-ha pastures were established in Upper Ruby Valley in southwest Montana in 1987 and 1988. A band of sheep grazed 1 pastu re in mid-June in both years. Sheep grazed 70% of larkspur stalks in 1 987 and 35% in 1988. Because sheep grazed little larkspur in 1988, lar kspur was hand decapitated to simulate the use obtained in 1987 for th e subsequent cattle grazing portion of the trial. Five cows were place d in each pasture immediately following sheep grazing in 1987 and afte r a 3-week delay in 1988. Cattle diets were quantified by bite counts. Waxy larkspur consumption by cattle in the sheep-grazed pasture was l ower than in the cattle-only pasture expecially during and after rains torms in 1987 and throughout the study in 1988. One cow died from lark spur poisoning in the cattle-only pasture in 1988. If sheep will graze waxy larkspur, subsequent consumption by cattle can apparently be red uced on this site, thus reducing the risk of poisoning.