BOISE, Idaho -

The Idaho Dairymen's Association is asking a federal judge to intervene in a lawsuit challenging a new law that makes it illegal to secretly film animal abuse at agricultural facilities.

The industry group filed a motion to become a defendant in the lawsuit late last week.

A coalition of animal activists, civil rights groups and media organizations sued the state last month, asking U.S. District Judge B. Lynn Winmill to strike down what they call an "ag gag" law. The coalition contends that the law curtails freedom of speech and makes gathering proof of animal abuse a crime with a harsher punishment than the penalty for animal cruelty itself.

Proponents of the law say it prevents animal rights groups from unfairly targeting agricultural businesses.