UPDATE 7:45 AM: Discovery CEO David Zaslav acknowledged this morning that ratings for OWN, the joint venture cable channel with Oprah Winfrey, were “below our expectations” — and that his company will have to spend more than the $215 million it has already invested. “It has been a slower start,” he told analysts in a conference call.” He added that “it’s going to take us a while, and we’re committed to it.” The company didn’t specify how much it would invest saying it will depend on OWN’s ratings. Meanwhile, Zaslav says that he plans to make big changes at Planet Green — the channel about environmentally friendly living. The concept “hasn’t worked out well. It’s underperforming.” Still, he’s upbeat about the upfront ad market as well as prospects to sell programs to services including Netflix and on platforms such as the iPad. “We’re unusual because we own all of our content,” he says. “We view all of those as opportunities.”

PREVIOUS, 5:36 AM: Add Discovery Communications to the list of television companies benefiting from the thawing ad market. The cable network power reports net profits of $305 million in the first quarter, up 76% vs the same period last year,  on revenues of $951 million, up 9%. The revenue increase comes to 12% if you just look at properties on Discovery’s books both years. The earnings represent  74 cents per share. Analysts that follow the company expected 47 cents in per-share earnings with revenues of $938 million.

CEO David Zaslav attributed the strong results to “our consistent investment in content over the past four years, along with a drive to expand our subscriber base domestically and internationally.”

Discovery also was helped by the fact that Discovery Health is no longer on its books: It was the foundation for OWN, the company’s joint venture with Oprah Winfrey. That added $102 million to net income, Discovery reported.