Zero fucks given is not exactly the same as "Its sausage to me". The German sentence "its sausage to me" would be better translated as "I dont care". Another difference is, that "zero fucks given" can be used to describe other people without explicitly addressing them (example: you and someone else observe someone doing something and you can literally say "zero fucks given" following any action and everyone else will understand that you meant the person you're observing). This is not possible with "it is sausage to me". The sentence structure changes completely when you try the same thing with it.
In theory you can use them in the same situations, but I would say, that "its sausage to me" gets mainly used for describing oneself and not other people.
