I worked very briefly on the IT team working for APHIS, and we had no interest in controlling people or farmers, but we had a big interest in finding contaminated meat. Your concerns are not matched by the intentions of the U.S. Department of Agriculture. If you want to make sure that such chipping would not be abused, then the enabling legislature can be written to assure that the data only be used for animal health measures, not for taxation or other controls. The Federal Government, believe or not, is very scrupulous about using information lawfully — IF the legislation is drafted well.
Oh please, peddle your “We’re from the government and we’re here to help you” carp somewhere else.