Wives of Anthony Brown and Ken Ulman explain why their husbands are running together in Maryland's gubernatorial race. (Brown-Ulman for Maryland)

Maryland gubernatorial hopeful Anthony G. Brown’s latest television ad is the first to feature his running mate, Howard County Executive Ken Ulman.

The 30-second spot, unveiled by the Democratic ticket on Friday morning, is narrated by their wives, Karmen Walker Brown and Jaki Ulman, who praise the team’s commitment to public service.

It comes at a time when both Brown, the state’s lieutenant governor, and his Democratic rival, Attorney General Douglas F. Gansler, have started airing negative ads in advance of the June 24 primary, which also includes Del. Heather R. Mizeur (Montgomery).

“Ken signed up with Anthony because they both believe that together they can make Maryland great,” Jaki Ulman says in the spot, which features pictures of both families and shots of the two candidates touring a business.

Ulman joined Brown’s ticket as his lieutenant governor candidate about a year ago.

Mizeur’s first television ad includes shots of her running mate, the Prince George’s pastor Delman Coates. Gansler has used his running mate, Del. Jolene Ivey (Prince George’s), in radio spots and in Web videos, but she had not yet played a starring role in a TV ad.