Talltimber I have had both dogs and horses with the condition that you have described.
In horses they call them "Roarers" and in dogs it is called "Laryngeal paralysis."
I won't get into the surgical treatments that were performed on them, because it would not be practical for a cow.
It happens when one (or both) of the flaps that close over the trachea become paralyzed. The flaps close the airway when you swallow and open when you breath. (Preventing food from entering the lungs.) It can be caused by injury or illness. (Possibly other reasons that are unidentified also.)
They can live many years with this condition, depending on the severity. But for the animals that I have had affected, aspiration pneumonia was a result.
Good luck with her, I hope that she continues to do ok for you.