Sanofi-aventus (the parent company of Merial) and Merck (the parent company of Intervet/Schering-Plough) announced today that their plans to merge the two animal health divisions into a new animal health venture have been terminated.

Plans for the merger were announced March 9, 2010. As a result of the termination, each company will retain "current, separate animal health assets and businesses," according to a joint press release from the parent companies.

The companies cited "the increasing complexity of implementing the proposed transaction," as well as the long time span it would take to endure a worldwide regulatory review process, as reasons for the termination. Both companies believe the termination is in the best interest of their businesses, their employees, and their shareholders, according to the news release.

The release relayed that sanofi-aventis will continue to develop the Merial brand as a "growth platform of its diversified health business." Merck relayed that it plans to continue work on "Intervet/Schering-Plough’s broad and innovative portfolio going forward