Hi New Maple Farm,
Welcome to the forum !
It's a bit hard to make any suggestion as to the cause of the white poop without knowing more, are you sure it came from one of your cows and if so which one ? If you told me you had a new calf I'd have thought the probable cause to be due to the calf's milk/colostrum diet otherwise I really don't know what to say.
Sorry not to be of more help, maybe one of the other members has a suggestion ?!