JEFFERSON CITY • Rural legislators and agricultural groups have sought for years to guarantee the “right to farm” in Missouri by making it part of the state constitution.

Their chief goal: to ban ballot initiatives such as Proposition B, the Missouri dog-breeding law that passed in 2010 after being bankrolled by the Humane Society of the United States and other animal welfare groups.

On a 110-41 vote, the House easily signed on to a proposed ban on such initiatives in February. But last week, the Senate threw the farm groups a curve.

In a compromise aimed at averting a filibuster, the Senate approved a new version of the constitutional amendment. It would preserve the right of groups to propose agricultural initiative petitions while declaring that the right “to engage in farming and ranching practices shall be forever guaranteed in this state.”

“It takes out the troublesome part for those of us that had real concerns, but at the same time, I think it gives (farmers) some protection,” said Sen. Jolie Justus, D-Kansas City.

The Senate passed the proposal 32-1. It now returns to the House, where some representatives are unhappy with the changes. They plan to seek a conference committee to negotiate with senators.