The American Dairy Association is a registered name owned by Dairy Management Inc., which also owns the names National Dairy Council and U.S. Dairy Export Council. It should not be confused with various state-level and regional 501(c)(6) organizations with similar names (such as, "American Dairy Association of Nebraska").
The National Dairy Council website offers a collection of educational materials  such as dietary guidelines, protein, maintaining a healthy weight, lactose intolerance, and the connection between dairy and sports. They also provide informational kits to health care professionals.