After the drought of 2011, so much clover came up in the pastures the next spring - no grass to compete with - that we had a problem with bloat. We only lost one steer, but there were dead cows in pastures all over the county. I don't want that again so I try to keep the clover in check, and in the process reduce many other broadleaf weeds that compete with the grass and are of no value to the stock.
