By Mark WeinraubCHICAGO, Dec 24 (Reuters) - U.S. cattle futures rose for the sixth time in seven sessions on Thursday, hitting a six-week high on signs of strength in the cash market, traders said.Hog futures eased after four straight days of gains pushed the front-month contract to its highest in nearly two months on Wednesday.Volumes were light in a shortened trading session ahead of Christmas.Chicago Mercantile Exchange February lean hogs fell 0.9 cent to 66.95 cents per pound. The contract found support at its 50-day moving average.