Color Communicates Well
Katie Grinstead from Wisconsin has this system of using color to communicate.
They feed different volumes of milk to their calves depending on their age. Thus, some calves are fed two quarts each feeding while others receive three quarts.
Pink pails = two quarts
Blue pails = three quarts
The link to her presentation is https://www.youtube.com/watch?v=O9r86l_vTp4
Another dairy, this one in central New York, has three different color pails:
Blue pails = two quarts
Yellow pails = three quarts
Red pails = calves being weaned, milk only in morning.
This is the principle of keeping routines as simple as possible - no words needed - just look at the color.