Nick Jr. has prolonged been wire television’s No. 1 channel dedicated usually to preschool children. The service, owned by Viacom, had a pound strike in “Dora a Explorer,” that done a entrance in 2000. Competition was also light: a Walt Disney Company, rapt with sport for preteenagers, operated no 24-hour preschool channel.

But in a year given Disney introduced Disney Junior, a channel directed during a minute of viewers, Nick Jr. ratings have plummeted some-more than 50 percent, according to Nielsen. On Tuesday Nielsen information for Disney Junior will be suggested for a initial time; a new channel is approaching to kick a rival, even yet Nick Jr. is accessible in 75 million homes, 25 percent some-more than Disney Junior.

Disney now has a tip 3 preschool wire programs, led by what appears to be a monster-size new hit, “Sofia a First,” a animation that stars a pint-size princess and her crazy animal friends.

Although ad income is tiny — Disney Junior accepts singular sponsorships; Nick Jr. allows promotion directed during mothers, though usually a bit — a intensity boon in a fondle aisle is huge. Even during 13, “Dora a Explorer” generates about $1 billion annually in tellurian sell sales. “People have been observant ‘Dora is dead’ for years, though a aged lady still has a clever following,” pronounced Chris Byrne, a fondle analyst.

Merchandise associated to Disney Junior shows is already throwing glow among retailers. Disney pronounced it approaching sales to transcend $1.5 billion in a stream mercantile year, a 50 percent boost from final year.

“A massive, large success” is how Richard Barry, arch merchandising officer for Toys “R” Us, described products associated to “Doc McStuffins,” a new Disney Junior hit about a lady who runs a hospital for her toys. One doll sole out so quick it shortly traded on eBay for $300.

Animated preschool shows also pull clever audiences in reruns, and some easy dubbing creates them a profitable abroad export. Beyond all of this, a value of destiny code faithfulness is incalculable. Anne M. Sweeney, boss of a Disney-ABC Television Group, has devised her fast-growing TV portfolio to keep children as they grow, only as Viacom tries to offshoot toddlers into a Nickelodeon family.

Disney’s wish is that they will start with Disney Junior; quit to a Disney Channel, directed during ages 6 to 14; and afterwards pierce on to boy-centric Disney XD or ABC Family, that is on a prohibited strain of a own. “These children are a Walt Disney Company’s many critical audience,” Ms. Sweeney said. “They’re a future, and this is their initial introduction to a brand.”

Preschool radio has prolonged been a severe and decrease playground, with broadcasters competing opposite pretender wire channels. Children ages 2 to 5 spend an normal of 32 hours in front of a TV any week, according to Nielsen. But foe is increasing. For media companies, this represents an area of expansion and, as some-more children pierce to mobile devices, there is some-more vigour to keep their attention.

The conflict has changed to apps, with Nickelodeon, Disney and Sesame Workshop, writer of PBS’s “Sesame Street,” competing to flue preschool shows to iPads — by some measures a new electronic baby sitters.

Nickelodeon in sold is fighting behind during Disney Junior. Last month, it denounced 4 new preschool programs, including a spinoff of “Dora a Explorer.” Another new array called “Wallykazam!” tries to learn literacy, embedding a reading curriculum in a tract that involves a child and his pet dragon, Norville.

Not to be counted out is Sprout, a channel mostly stocked with PBS shows like “Thomas Friends” that has grown steadily given apropos partial of NBCUniversal in 2011. Sprout is pulling new sell of a possess and has increasing selling efforts, entering a float, for instance, in final year’s Macy’s Thanksgiving Day Parade.

Preschool party is a politically ethereal area filled with advocates who boomerang during TV directed during children as immature as 2. “There continues to be a lot of stress from relatives over how most TV is too much,” pronounced Dade Hayes, author of “Anytime Playdate: Inside a Preschool Entertainment Boom, or How Television Became My Baby’s Best Friend.”

Even so, Mr. Hayes, who is also executive editor during a trade announcement Broadcasting Cable, remarkable that there had been surprisingly small commotion over “Sofia a First.” That uncover was deliberate risky since — while secure in training amicable skills — it is some-more driven by party than sincere education. Princess Sofia, wearing a purple robe and tiara, attends a prep propagandize run by a 3 fairies from “Sleeping Beauty.”

Nickelodeon’s preschool offerings are famous for enchanting characters churned with eat-your-broccoli educational messages; one hit, “Ni Hao, Kai-Lan,” aims to learn children some Chinese. “We were in a trenches articulate to kindergarten teachers and mind experts,” Teri Weiss, executive clamp boss for prolongation and growth during Nickelodeon Preschool, pronounced of a growth of “Wallykazam!”

She added: “There are competitors that dally in education.”