Is it wrong to have an animal put down when it is suffering and may be incurably ill?

Unlike human animals cannot understand the nature of suffering and in the case of household pets the owners are responsible for their wellbeing. If an animal is suffering from some malady which veterinary science cannot alleviate, then it is better to have it painlessly put to sleep. Human beings have a direct responsibility for the welfare of the animal kingdom and individuals are answerable for the way they face up to this responsibility.