Discovery Communications, half-owner of Oprah Winfrey’s cable network, OWN, fell the most in six months as profit fell short of analysts’ projections following more losses at the fledgling cable channel. The shares dropped 6.1 percent to $50.80 at the close in New York, but rose 6.3 percent to $53.99 in after-hours trading. Discovery reported it assumed 100 percent of the losses at OWN in the first quarter. The stock has gained 24 percent this year.