AP - Manure spread on a frozen field is blamed for killing dozens of brown trout in a southern Wisconsin stream, just months after the federal government removed the river from its list of impaired waters.{br}{br}View the Entire Article (http://us.rd.yahoo.com/dailynews/rss/science/*http://story.news.yahoo.com/news?tmpl=story2&u=/ap/20050302/ap_on_sc/manure_rules){br}