Mh. Ralphs et Jd. Olsen, PRIOR GRAZING BY SHEEP REDUCES WAXY LARKSPUR CONSUMPTION BY CATTLE - AN OBSERVATION, Journal of range management, 45(2), 1992, pp. 136-139
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.