If you have a pet you will know how much they give out in terms of love and company - just by being. They soak up our bad moods and give love unconditionally.
Although they do deal with trauma better than us - they naturally shake after a particularly distressing experience - domestic animals especially, have a similar range of emotions to us and these can become trapped in them just the same as with us.
If you have taken in a rescue animal it would be of great help to them to have their trapped emotions released.
Other circumstance in which it would benefit your pet to lose any emotional baggage would be
if it's had surgery, or had to spend time in kennels, or you have moved home, or introduced a new pet or a new baby - bascially anything that is a major change.
It is easy to carry out this clearing and will allow your pet to rebalance on all levels - which is beneficial for its physical health and condition and more importantly - happiness.