The state plans to appeal an Upper Peninsula judge's ruling that overturns a ban on Russian boars and similar swine breeds.
The attorney general's office asked the Michigan appeals court to take the case Friday. The state says Judge Thomas Solka of Marquette County made errors in his March 24 decision.
In 2010, the Department of Natural Resources designated exotic swine as invasive species that are off-limits in Michigan. The DNR says they're escaping into the wild from game ranches and small farms and damaging the environment.
But the judge says the policy is vague and leaves unclear which swine are covered. He declared it unconstitutional.
Owners had challenged the DNR order, saying they're being unfairly blamed because their animals are not getting out.