Dog abuse doesn't just include the cut-and-dried example of a person physically beating a dog. There are a number of methods of abuse to dogs, including from people who may not necessarily intend to harm the animal. There's also contention about some treatment to dogs that some consider abuse, but is not considered abuse in the eyes of the law.
What Constitutes Physical Abuse
The most blatant example of dog abuse is physically striking a dog. Some people injure stray dogs or kidnap neighborhood dogs in order to torture them. However, people who adopt dogs intending to provide them with loving homes may abuse them as well. Owners who find themselves getting fed up with poor behavior in dogs may slap them, hit them or otherwise injure them out of anger. This is abuse and is ineffective in the long run at correcting the behavior.
What Constitutes Emotional Abuse
Some people take out their stress on dogs, thinking the dog won't understand if something is yelled at them. Dogs may be unable to understand exactly what is said to them, but they can interpret moods and they can be emotionally abused. Emotional dog abuse is yelling, screaming or shouting forcefully at a dog when the situation doesn't call for it.
Effective behavioral training may involve firmly bellowing, "No!" when the dog is behaving poorly, but if there is no bad behavior going on, the owner should not be trying to intimidate the dog. The dog will get mixed messages and be unable to learn proper behavior because it won't make the connection between the bad behavior and the bad reaction in the owner.
What Does Not Constitute Abuse
Some people object to some treatment of dogs because they think that it constitutes abuse. However, training an animal for a specific job, such as a police dog, a rescue dog, a guide dog or even a dog that performs tricks for entertainment is not dog abuse, so long as the dog is treated well and trained with a reward system and not an egregious punishment system. In fact, some breeds of dogs love having these kinds of goals in their lives.
Areas that are often a bit more contentious include testing on dogs (for medical, cosmetic or other purposes) and breeding dogs in "puppy mills." While the individual may choose to object to these kinds of situations, they do not always constitute dog abuse, so long as the people in charge adhere to humane practices. If someone suspects that the people involved are not adhering to humane practices, that person should call the ASPCA to recommend an investigation.
The Effect of Abuse on Dogs
The effect of physical abuse on a dog tends to be obvious; physical abuse can lead to injury, including permanent disability and death. However, if caught in time, it's possible to save a dog's life from physical abuse.
The emotional effects of both physical and emotional abuse are much tougher to treat and can be just as devastating. Abuse typically causes a dog to either become extremely withdrawn and distrusting of humans or aggressive toward humans and other animals or both. A behavioral specialist can sometimes work with abused dogs, but may not be able to make them adoptable again.