For the Native American Indians, "dog days" refer to the time before the whites came to this country, before they had horses. The Plains Indians used dogs to pull their travois and their teepees when they moved following the buffalo. So when the horses came (stolen or escaped from their white owners) the Indians had a better way of life. The horses were better for hunting and warfare, etc. So from the native point of view, "the horses are coming" means change is coming, good days are coming. The "dog days" are over meaning your old way of life is over. Which is good in a way, but hard as well, because with the horses came the white man.