To go even farther off on a tangent - When I was a child my parents took in a starved and dehydrated mare with an hours old foal. The mare did not have any udder development and we were concerned she was not producing milk. Once fed and watered, she did produce milk. The foal nursed and thrived, but the mare never developed udders. The foal was consuming the milk about as fast as she was producing it. The foal’s growth and development were quite normal, so she was producing adequate milk.