MADISON, Wis. (AP) — Rod Nilsestuen, who headed the Wisconsin Department of Agriculture as a "visionary agriculture leader" and helped dramatically increase the state's dairy production, has died, Gov. Jim Doyle's office said late Wednesday.

"It's our understanding that he drowned while volunteering and working on a Habitat for Humanity home in Michigan with family," Doyle spokeswoman Carla Vigue said.

Police in Marquette, a city in Michigan's Upper Peninsula, said they responded to a drowning Wednesday evening near Picnic Rocks, a recreation area along Lake Superior. Police said the victim was a Wisconsin man visiting the area, but his name hasn't been released. Vigue said Nilsestuen was volunteering in the area.

Doyle appointed Nilsestuen secretary of the Wisconsin Department of Agriculture, Trade and Consumer Protection in 2003.

Nilsestuen was not only "one of the most important agriculture leaders in Wisconsin history" who helped protect farmland and connect residents to local farms, but also was a wonderful father, husband and friend, Doyle said in a statement.

The governor credited Nilsestuen for dramatically increasing Wisconsin's production of cheese and milk, promoting the development of biofuels to generate local renewable energy and ensuring that "farmers received the economic value of their work."

"Under his incredible leadership, Wisconsin has seen the greatest and most beneficial transformation of agriculture in generations," Doyle said.

Nilsestuen also was a respected leader in the cooperative movement. Before he became the state's top agriculture official, Nilsestuen spent 24 years leading the Wisconsin Federation of Cooperatives, according to his biography on the department's website.

He also helped found a national cooperative task force that resulted in federal investment in cooperative development, and held leadership roles in several regional and national cooperative groups, the biography said.

He was a graduate of the University of Wisconsin-River Falls, and earned a law degree from the University of Wisconsin-Madison, according to the biography.

Copyright 2010 The Associated Press.