Elimination of residual molybdenum in cattle exposed to high molybdenum forage

The elimination of molybdenum (Mo) from tissues of cows grazing extremely high Mo forage (>100 ppm Mo dry weight) at the Highland Valley Copper mine in British Columbia, Canada, was measured to determine when these animals could be accepted for slaughter to produce meat suitable for human consumption. Molybdenum levels in muscle and fat were 10-fold lower than those in liver tissue. The results demonstrated that muscle and fat tissues would be acceptable for human consumption after 1 mo, but a clearance period of 3 mo prior to slaughter would be required before the liver could be introduced into the food chain.