An audit report made public recently charges the Agriculture Department with failing to properly track hundreds of imported cattle despite continuing cases of mad cow disease in Canada, The Chicago Tribune reported Wednesday.

Paul Feeney, a spokesman for the inspector general, says auditors are not sure how many cattle have entered the country improperly. The audit report covered the fiscal year ending in September 2006, when about 1 million cattle were imported from Canada.

Mad cow disease was discovered in a dairy cow imported from Canada in Washington state in 2003. Since then two more cases have been reported in the United States, one in a Texas-bred cow and another in Alabama.