They certainly enjoy eating their own afterbirth (slurp sluuurrp). First time I saw that I was probably age 5. My sis (3 yrs older) still remembers me standing there, eyes and mouth wide open. I remember my sons first times and reactions. Lol
I think I read somewhere that it activates and tells the mammary glands it is time for nursing. Most mammals do that.
We called it cleanings.
When grain got short at the end of the year, we mixed in sawdust. Not much in nutrition, but is was a filler and stretched out the grist for a while until we go them onto pasture in the spring.
BTW, in Germany during WW2 the made liver wurst out of wood pulp. I think it was liver wurst. The Brits used it to mix in with bread.