How does Katherine Anne Porter use imagery in Holiday?

Porter weaves animal similes and metaphors throughout the story, both likening people to animals and vice versa. When Hatsy and Mother Müller milk the cows, for example, their first task is "separating the hungry children from their mothers." After Hatsy pulls the calves away from the cows, the calves bawl "like rebellious babies." Later in the story when Gretchen gives birth to a son, Porter turns the comparison around: "The baby bawled and suckled like a young calf."