If the cowboy wore a coat he would wear it open and loose as much as possible.

If he wore a "vest" he would wear it slouchily, hanging open or partly unbuttoned most of the time.

There was a reason for this slouchy habit.
The cowboy would say that the vest closely buttoned about the body would cause perspiration, so that the wearer would quickly chill upon ceasing exercise.

If the wind were blowing keenly when the cowboy dismounted to sit upon the ground for dinner, he would button up his waistcoat and be warm.

If it were very cold he would button up his coat also.
The cowboy's boots were of fine leather and fitted tightly, with light narrow soles, extremely small and high heels.