In the prologue of A Game of Thrones, we are introduced to different types of horses:
Will went in front, his shaggy little garron picking the way carefully through the undergrowth. A light snow had fallen the night before, and there were stones and roots and hidden sinks lying just under its crust, waiting for the careless and the unwary. Ser Waymar Royce came next, his great black destrier snorting impatiently. The warhorse was the wrong mount for ranging, but try and tell that to the lordling. Gared brought up the rear. The old man-at-arms muttered to himself as he rode.
Later on in the books while describing Stannis' march, it is mentioned that the shaggy garrons are good for the colder climate. The war horses are too big and don't handle the cold well. Yet in S8, the Dothraki horses seem to be handling the cold very well.
Are the Dothraki horses closer to a warhorse or a garron or something else? Is there a reason that they can handle the cold in the North so well?