It's time again to find out who's top dog

The best dogs in the country are in New York tonight for the Super Bowl of dog shows.

The 134th Westminster Kennel Club pooch parade runs tonight and Tuesday night on cable.

Going in, the favorite to win best in show is Sadie, a 4-year-old black Scottish terrier (registered as Ch Roundtown Mercedes Of Maryscot) who already has won 100 Best in Show competitions in her short career.

Other top dogs on her tail include a Doberman, a golden retriever, a fox terrier and a Puli (a breed that looks like a walking dust mop).

Also, three new breeds will be introduced: the Irish red and white setter, the Pyrenean shepherd, and the Norwegian buhund. The newcomers bring this year's show total to 173 breeds and varieties.

Entries this year total 2,500 dogs representing 48 states, the District of Columbia and at least eight foreign countries. The most-represented breed is the Australian shepherd with 44.

Dog expert and longtime voice of Westminster, David Frei will be back for his 21st consecutive year as commentator.

Mario Lopez, of "Extra," was to have replaced NBC's Lester Holt as a co-host (Holt has Olympics duty) but Lopez had a conflict. Newcomer Tamron Hall, a morning anchor on MSNBC, has stepped up to the job.

Coverage begins at 8 tonight on USA but switches to CNBC at 9 p.m. because USA just can't give up Monday night wrestling.

On Tuesday, USA will air all three hours from 8 to 11 p.m., including the crowning of the 2010 Best in Show. For details, go to www.westminsterkennelclub.org.

DEAD ZONE: This is the time of year when the broadcast networks start planning for next season and series that aren't doing well are put on the endangered list.

It's almost a safe bet that NBC's "Heroes" won't be back. The CW probably won't renew "Smallville" and the network's potboiler "Melrose Place" appears doomed.

Its curtains for CBS's "Numb$rs" and the network should cancel "Accidently on Purpose."

Trade publications such as The Hollywood Reporter and Variety have handicapped the winners and losers, and about 20 series are, as they say, on "on the bubble."

Speculation is high that Fox's "24" won't be back.

Others in trouble, according to those in the know, include ABC's "FlashForward," CBS's "Cold Case" and "The New Adventures of Old Christine"; and NBC's "Community" and "Mercy."

OFFICE BABE: NBC has announced a special hourlong "The Office" titled "The Delivery Part 1 and 2" that will air March 4 at 9 p.m.

Pam's (Jenna Fischer) contractions begin but she and Jim (John Krasinski) are determined to wait it out so they can have more time at the hospital.

Meanwhile, the rest of the office tries to distract Pam from the pain with food and entertainment.

In the second half hour, Michael (Steve Carell) anxiously waits for couple's baby to be born.

TRIVIA MOMENT: This will make some of you feel old. Actress Mayim Bialik, a teen star in the '80s, joins "The Secret Life of the American Teenager" (8 p.m. on ABC Family) as the new school counselor. Now 34, she starred in NBC's "Blossom" from 1991-95.

TUNE IN TONIGHT

Winter Olympics, 8 p.m., NBC

Figure skating, speed skating, luge and snowboarding are on the schedule. Look for Florida pairs figure skaters Caydee Denney and Jeremy Barrett, and Amanda Evora and Mark Ladwig.