AMC Networks (AMCX) said Thursday its first-quarter earnings surged 43% on substantially higher advertising sales at its national networks.

Shares climbed 5.7% to $68.365, as the earnings report beat Wall Street estimates.

The cable channel operator, which was spun off from Cablevision Systems (CVC) in 2011, has found success in creating original shows, such as “The Walking Dead” and “Mad Men,” that have climbed the ratings charts. However, AMC Networks has incurred higher costs as a result.

The company owns three other networks: the Sundance channel, WE and IFC.

AMC Networks recorded a $61.5 million profit, well above the year-ago period’s $43.2 million profit. Per-share earnings for the latest period were 85 cents, up from 60 cents. Analysts expected earnings of 80 cents a share.

Revenue jumped 17% to $382 million, beating estimates of $367 million.

The national networks segment posted revenue growth of 18%, led by a 27% increase in advertising sales.

In a statement, President and Chief Executive Josh Sapan said the first quarter was “driven by our popular original programming that is resonating with an increasing number of viewers and advertisers.”

He added that “The Walking Dead” was the highest-rated show during the broadcast season for adults 18-49, and ratings were up 55% from the prior season.

Follow Matthew Rocco on Twitter @MatthewRocco