Like us, animals can take on, or be influenced by, the energy of other animals and people around them, past or present, still living, or in spirit.
Most animals shrug off other, unrelated energies, like we do. But some individual animals can be more susceptible than others. This may be because of their heightened sensitivity or an especially loving nature, or more often because of a traumatic experience or past history that has left them more vulnerable and open to them.
Either way, occasionally they do arise, and when they do it's important to release these energies and then help them to build up an animal's protection against their recurrence.
When working with an animal, typical signs of a spirit, entity or energy attachment might be a sudden change of energy felt over parts of the body, or a sudden change of personality or attitude during a communication. Imagine talking to a friend who seems relaxed and happy, and then suddenly for no apparent reason they say something to you that's completely negative and out of character. Then afterwards, they might say, "I don't know what came over me." That's what an 'energy attachment' can sometimes feel like.
I would be considering the possibility of an energy attachment with any of the following symptoms:
A sudden change of energy felt on the body
Mood swings and 'Jekyl & Hyde' type behavioural changes
An extreme behavioural reaction with no physiological or psychological cause
Heavy sadness, despondency, depression, apathy
Loss of interest or motivation
A feeling of 'not being oneself'
Whether or not you are familiar with the concept of these 'entities' or attachments, it is evident that the removal or release of such energies can result in a sudden and significant positive effect on an animal's behaviour.