It is the day all pit bull owners in Ontario knew was coming but didn’t want to see.

The province’s controversial new legislation banning the breed took effect Monday, making it illegal to bring any kind of animal considered to be pit bull-like here.

Existing pets will be able to remain for the rest of their lives, but will have to be kept on a leash and muzzled in public, and owners will have to neuter the animals.

There’s a two month grace period, meaning puppies born here up to November 27th can stay. But those who defy the law or whose dogs attack people can have their pets seized and destroyed. Owners can also face possible jail time and fines up to $10,000.

The new law puts teeth into what some consider a dangerous and unneeded breed, but pit bull lovers believe it unfairly discriminates against responsible dog owners with good animals, and they plan to challenge the law in court.

And they’ve hired a legal pit bull of their own – high profile attorney Clay Ruby is planning to represent them in court.

Many gathered for a candlelight vigil with their canines at Queen’s Park late Sunday, to show solidarity and protest the ban. They brought their unmuzzled dogs with them for the last time.

"Now when I walk down the street, people are going to look at him like he’s a vicious dog, like I’m a vicious owner," worries Jordan Haynes. "You know, he plays with 20 dogs a day. He’s not a vicious dog."

The bulk of their complaints rest with the fact the law doesn’t properly define just what a pit bull is, a definition even breeders can’t entirely agree on.

"The breed-specific legislation is unacceptable," complains Natalie Kemeny, co-founder of Advocates for the Underdog, a dog rescue group in Windsor, Ont. "I don't believe it's going to solve the problem in Ontario.”

She fears bad owners will simply turn to another potentially vicious breed.

But while many people oppose the ban, those who’ve had a terrible experience with the dogs believe the new law will make Ontario a safer place.

"In urban settings where you have dense communities where there are children, I think it’s probably a good solution," agrees dog owner Jennifer Sutherland.

Louise Ellis has more reason than most to support the law. Her then five-year-old daughter was attacked by a pit bull 11 years ago. It took about 300 stitches to close the girl’s wounds.

"I've seen enough," she concludes. "I'm glad the law is finally coming into effect."

• It is illegal to own, breed, transfer, abandon or import pit bulls.

• A pit bull terrier is defined as a Staffordshire bull terrier, an American Staffordshire terrier, an American pit bull terrier or any dog that has an appearance and physical characteristics that are substantially similar to those dogs. The onus is on the owner to prove the family pet is not a pit bull.

• Pit bulls already owned in Ontario before Aug. 29, or born in the next 90 days, are deemed "restricted" and can stay in the province. They must be leashed and muzzled when in public, and spayed or neutered. Owners of these animals are prohibited from allowing their dogs to stray and cannot train them for fighting. The law includes a 60-day grace period -- ending Oct. 28 -- to allow owners to comply. Registered purebreds are exempt from being sterilized as long as they show regularly. A dog deemed physically unfit for surgery by a veterinarian because of old age or infirmity is also exempt.

• Those who violate the ban can have their pit bulls seized and destroyed. The owner of a dog that's deemed dangerous, regardless of breed, is subject to fines of $10,000 and a jail term of up to six months.

• If a person didn't own a pit bull as of Aug. 29, they can still acquire one restricted dog either through adoption or bequest. Those with restricted pit bulls at that date can acquire other restricted dogs, but they can never own more than they did as of Aug. 29th.

• Puppies born after Nov. 27th will be considered illegal. They must be shipped out of the province, sent to a research facility or destroyed.