MOLYBDENUM POISONING IN FEEDLOT CATTLE

Objective to describe a case of acute, fatal molybdenum poisoning in f eedlot cattle. Description of the herd In total, 831 Hereford, Herefor d x Angus, and Hereford x Simmental steers, aged 8 to 10 months, with an average body weight of 310 kg were fed a diet, to which sodium moly bdate at a rate of 1.9 % of the total ration had been accidently added . Investigation The steers lost appetite within 3 days and deaths comm enced within 6 days of the diet being first offered. The error was rec tified when deaths started to occur, but steers continued to die for u p to 7 months afterwards. Of the 831 steers on the feedlot, 90 died an d a further 5 remained in poor condition. The cause of death was peria cinar to massive hepatic necrosis and acute renal tubular necrosis. Bl ood and tissue samples were taken from surviving steers for 76 days, b y which time plasma molybdenum concentrations had returned to normal c oncentrations. Conclusion Sodium molybdate when fed at a rate of 1.9 % of the diet results in acute renal tubular necrosis and periacinar to massive hepatic necrosis.