Pard, you might be thinking about They Came To Cordoba with Gary Cooper, Rita Hayworth, Van Heflin, Tab Hunter and Dick York in which a group of U.S. soldiers, led by Cooper have their horses stolen by Mexican bandits or your could be thinking of 3 Godfathers with John Wayne, Harry Cary and Pedro Armendiaz, in which 3 outlaws have lost their horses and find a dying woman giving birth in the desert.