Animal Abuse is suffering or harming of a non-human animals, not for self-defense.  It is not considered to be abuse if it is food, clothing, entertainment, and research as long as it is done in a humane way that doesn't have unnecessary pain and suffering.  In some countries animal cruelty is not allowed at all but others use it as practice or use.  There are two kinds of abuse towards animals active and emotional. Active abuse is Physical harm towards the animal, and emotional abuse is like yelling at them in an enclosed area .

Most cruelty is ignoring your animal like not feeding it, and giving it water, and not giving any care at all.  Example of neglect is starvation, dehydration, parasite infestations,  letting the collar sink in to the animals skin, the wrong shelter in extreme weather, and not seeking veterinary care when needed.  Some of the cruelty towards animals is because of people with disorders.  Some county's  torture or abuse animals for practice of religion in ancient cultures. 

Animal abuse doesn't just happen at home circuses and films with animals in them can be getting abused as well.   Some movies with killing scenes and include killing chickens and bled horses from the neck to smear on the for the film heaven’s gate.  In circus's they abuse the animals by keeping them in confining enclosures, lack of veterinary care, and abusive training methods.  They shout at the enclosures in a cruel way harming them mentally.  They also have fighting between animals like dog fighting, bull fighting, etc. The animals can suffer from severe stress and a slow painful death.