NEW YORK — Branding is all the rage among cable and satellite entrepreneurs throughout the world, and one of the better-known brands — National Geographic — has joined up with NBC to create 24-hour ad-supported natural history networks in Latin America, Europe and Asia.The 50-50 partnership links the hundreds of hours of docu programming in National Geographic’s library with the worldwide distribution clout of NBC, which owns NBC and CNBC channels in Europe and Asia, and Canal de Noticias in Latin America. “We’re not starting from scratch,” Tom Rogers, president of NBC Cable, said in a conference call with reporters Wednesday to announce the pact. “We won’t be stuck with the huge costs of developing programming, and there won’t be the huge distribution costs — both of us already have so much of what we need to make these new channels successful globally.” John Fahey, president and CEO of National Geographic Ventures, said the alliance hasn’t targeted any specific countries yet. Rogers added that each new National Geographic channel will offer “an equity participation” to TV partners within a given country “who’ll bring with them the ability to get the channel locally distributed” and help with areas such as dubbing shows into foreign languages. Although wildlife and science documentaries will comprise the bulk of the programming, Tim Kelly, president of National Geographic TV, said the channels will sked nature series for children and fact-based original movies and miniseries like the ones it’s now developing with Hallmark Entertainment. The joint venture evolved out of “the relationships we share with National Geographic on a number of fronts,” Rogers said. NBC started running four original National Geographic specials a year in primetime in the U.S. in January 1995. NBC’s cable and satellite distribution service in Europe began running a branded block of National Geographic programming in September 1996. The NBC-National Geographic alliance will be taking aim at Discovery Networks Intl., which reaches 140 countries outside the U.S. and formed a joint global venture 10 weeks ago with the BBC to launch new channels in the U.S. and abroad.