Storms influence cattle to graze larkspur: an observation.

Abstract

Livestock producers report cattle deaths from larkspur (Delphinium spp.) poisoning increase during stormy periods. In controlled grazing studies, we observed cattle increase larkspur consumption during stormy weather. Periods of "gluttonous" larkspur consumption generally coincided with storms during a 1990 grazing study. Cattle consumed larkspur almost exclusively for 20-30 min periods during storms, as opposed to intermittent grazing of larkspur flowers, pods, and leaves. In 1991 weather parameters were measured and correlated with larkspur consumption. Larkspur consumption was negatively correlated with decreasing temperature and barometric pressure (r = -0.45 and -0.60 respectively); and positively correlated with increasing relative humidity, leaf wetness, and precipitation (r = 0.45, 0.74, and 0.27, respectively). Understanding consumption patterns of cattle grazing larkspur will aid in developing management strategies to reduce cattle deaths.