HELENA (AP) The Montana Department of Livestock says concerns about disease led the agency to impose a new rule on cattle from Canada if they are not merely passing through the state. The rule effective this week requires documentation that breeding cattle are free of brucellosis, tuberculosis and trichomoniasis. Also set forth are strict requirements for animal identification, including a demand that animal ID include hot-iron brands, not just tattoos. Officials say tattoos can become hard to read over time, and to examine tattoos animals must be restrained. The rule, similar to new rules in North Dakota and several other states, comes as the federal government this week began allowing cattle older than 30 months of age into the U.S. market. Some U.S. ranchers worried about mad cow disease oppose that action, which reversed a border closure the U.S. Department of Agriculture imposed in 2003 after mad cow disease was confirmed in an Alberta cow. Montana's rule drew praise from R-Calf USA, a Billings-based organization critical of the federal action reopening the border. "It's recognition that we cannot compromise our health and safety standards just to accommodate additional trade," chief executive Bill Bullard said Wednesday. A call seeking comment from the National Cattlemen's Beef Association were not immediately returned on Wednesday. Speaking earlier on the USDA's border decision, the National Cattlemen's Beef Association said the United States cannot expect higher standards from trading partners than the country is willing to impose on itself. A spokeswoman for the Canadian Cattlemen's Association said "We're not overly happy with" the tuberculosis element of the rule. Canada's government has declared the country's cattle TB-free, but that is not recognized inThe United States, spokeswoman Theresa Keddy said from Calgary, Alberta. Keddy said she lacked enough information to talk about the brucellosis and trichomoniasis features of the rule. Within months of the 2003 ban, the U.S.-Canada border reopened to Canadian beef from younger cattle. Since mid-2005 the border has been open to live cattle younger than 30 months. Older cattle carry a higher risk of having mad cow disease, a disorder that scientists believe is spread when farmers feed cattle recycled meat and bones from infected animals. Two o f t h e d i s e a s e s addressed in the Montana rule, brucellosis and trichomoniasis, can cause abortions in cattle. Bovine tuberculosis is a wasting disease of the lungs. While the Montana rule does not apply to animals passing through the state, it does apply "if they step one foot off the trailer," said Steve Merritt, spokesman for the Montana Department of Livestock.