SAGINAW, Mich. (AP) - Michigan authorities say tests confirm a case of bovine tuberculosis in a cow from a Saginaw County dairy farm. The Michigan Department of Agriculture and Rural Development said Thursday that a federal lab identified the disease in a cow spotted during slaughter surveillance. The herd is quarantined and all animals are being tested. The contagious bacterial disease spreads between cattle and wild deer. Michigan's 14,000 cattle farms have been tested since an outbreak began in the mid-1990s. The state says bovine TB is endemic in Alcona, Alpena, Montmorency, and Oscoda counties in the northeastern Lower Michigan. Saginaw County is about 115 miles from that zone. Michigan says it doesn't expect the finding to lead to a reclassification of Saginaw County as bovine TB free.