Abstract: A method for semi-quantitativly determining the ability of horses, mules, donkeys and zebras to sweat, which comprises intradermally administering a series of at least twofold dilutions of at least one pharmaceutical compound having .beta.-2 stimulator activity and substantially free of .beta.-1 and .alpha.-adrenergic activity to such animal, observing the skin over the injection area for the formation of sweat droplets, and identifying anhidrotic animals having inadequate thermoregulatory responses to hot, humid climates by the results thereof.