Despite a seemingly earnest effort, the government ends an unsuccessful investigation to track the origins of an Alabama cow infected with mad cow disease.

According to AP, seven weeks of investigation of more than three dozen farms ended with little answers.

In a separate investigation, notes the report, the officials will continue to trace 15 cattle imported from Canada that ate the same feed as an infected cow discovered last month in British Columbia. So far, the government has found one cow and intends to kill and test it, the Agriculture Department said.

John Clifford, the USDA's chief veterinarian, tells AP that it's important to remember that people and animals are protected by a series of safeguards in the United States.