After applying Decimate Modifie Key frame dispears or the orange/yellow lines atleast

Hi, thanks for helping me. After applying the Decimate Modifier on my model, the orange lines is gone but the Animation still plays, the only other modifier on the model is the Armature modifier and I have made sure the decimate modifier is on top when I applied it. How would I get them back? Because when I import the Model to this Game Engine, the animations are the model but they do not play. Thanks