Also, I like animals very much and I would like to help them when they suffer.
I also like animals very much and I would like to help them when they suffer.
Is also at the beginning of the sentence correct? Does it sound too formal to you?
Both sentences are fine to use. There has been a rule passed down through generations, incorrectly telling people that they must not use words such as but, or, and or however at the beginning of a sentence.
Using conjunctions at the beginning of sentences is not forbidden. And, you can choose to do this to emphasise a point. However, you need to be careful not to do it too much.