Euthanasia should always be performed by a veterinarian, according to both veterinarians and those with the American Society for the Prevention of Cruelty to Animals. An untrained pet owner who attempts to euthanize his dog may perform the procedure incorrectly, making the dying process more difficult for the dog.
There are multiple factors that affect the euthanasia process, including the dog's size, age and medical conditions. Unlike veterinarians, an untrained pet owner may not have a backup plan if something goes wrong during the euthanasia process.
Many veterinarians perform at-home euthanasia instead of requiring the dog to be brought into a veterinary clinic. This method can be less stressful on the dog, as it is in a familiar setting. It is also a convenient method when the dog cannot be transported easily, due to size or illness. This method can be less stressful for the owner because he doesn't have to take his dog to the clinic and be around strangers in the waiting room. It also helps any other pets in the family recover from their companion's death, as seeing the dog's body can give them closure.
The cost of euthanasia is one reason an owner may not want a veterinarian to perform the procedure. However, free or low cost alternatives are often available at animal shelters.