Impact of locoweed poisoning on grazing steer weight gains

Emaciation is one of the clinical signs of locoweed poisoning but few studi es have documented impacts of locoweed poisoning on weight gains. Stocker s teers (British x Continental cross, 200-210 kg) were grazed on locoweed-inf ested, short-grass prairie in 1996 and 1997 in northeast New Mexico. Each y ear, half the steers were averted to locoweed to allow them to graze locowe ed-infested pastures without eating locoweed. They did not graze locoweed a nd steadily gained weight (0.50 kg/day in 1996 and 0.71 kg/day in 1997), Th e other group of steers were allowed to graze locoweed under natural grazin g conditions and became intoxicated. Weight gains were not affected for the first 3 weeks, but thereafter the steers lost weight in both years. In 199 6, non-averted steers consumed locoweed for a season average of 20% of bite s. They were severely intoxicated and did not begin gaining weight for 50 d ays after they stopped eating locoweed, Steers in the 1997 trial consumed l ess locoweed (11% of bites) than those in 1996 and they recovered more rapi dly. Seasonal weight gains were 21 to 30 kg less for locoed steers than con trol steers in 1996 and 1997, respectively. Locoweed poisoning will cause w eight loss, and severely intoxicated cattle require a lengthy recover perio d after they cease grazing locoweed before weight gains resume. Stocker cat tle should not be placed on locoweed-infested rangelands until green grass is abundant and locoweed begins to mature.