If you're looking for a new pet, consider adopting a rescue dog. Dogs from the shelter often come trained, vaccinated, and spayed or neutered. Choosing adoption also means taking business away from puppy mills and potentially saving an animal's life.

Pet adoption is gaining popularity, but animal shelters still have trouble finding homes for their underdogs: The dogs who are often overlooked because they're older or disabled. To raise awareness of this group, the pet food company Petcurean is holding their second annual Uplift the Underdog contest, a competition that helps underappreciated and highly adoptable dogs find their forever homes.

To nominate a dog for the contest, rescue groups and shelter organizations in Canada and the U.S. can enter their candidates' information online. Finalists will be placed in one of three categories: senior dogs, dogs with medical challenges, and dogs with behavioral or emotional issues. The public will be able to vote on the 18 finalists (six in each category) beginning April 30 (which is National Adopt a Shelter Pet Day), and the three category winners will be announced on May 7.

The top three underdogs will win a five-year supply of dog food. All finalists will receive a makeover, a 50-pound donation of pet food to their shelter, and a one-year supply of dog food and covered adoption fees if they find a home by the end of 2019.

“There are so many amazing dogs that are just waiting for their chance to be adopted, but due to stereotypes associated with shelter pets, particularly ones who are not considered 'perfect,' they’re overlooked time and time again,” Petcurean's PR and community relations manager Christine Mallier said in a statement. “Our hope is that the ‘Uplift the Underdog’ contest will not only encourage people to adopt these deserving dogs, but that it will also raise awareness for the groups that are working so hard to support the displaced animals in their communities.”

Shelters have until April 14 to nominate eligible pets. And if you're still not convinced that adoption is worth it, here are some before-and-after pictures of rescue dogs that might just change your mind.