Switching formula brands or types of formula can sometimes cause fussiness in babies.
However sometimes switching formula can cure fussiness in a baby especially if the babies stomach doesn't agree to the certain type of formula you're feeding them.
So if your baby is fussy during feedings you could try switching to a different brand of baby formula and it can sometimes stop the fussiness.
You can also feed your baby some Carnation Evaporated Milk which was fed to babies years ago and they thrived really good on the Carnation Evaporated Milk.
Carnation Evaporated Milk helps to settle babies who're fussy during feedings.