Abstract: The invention provides a method and apparatus using infrared thermography for predicting an unknown value of an internal composition characteristic of velvet antler in vivo, in vitro, and/or during cooling or warming. The method involves generating a predictive model using a sample population of antlers to determine a relationship between a known input variable and a known value for the composition characteristic; and using the predictive model to predict the unknown value of the same composition characteristic in an antler not selected from the sample population. Using this value, a map can be made to identify sites and levels of the composition characteristic within the antler. The invention provides a method for predicting an internal composition characteristic of a velvet antler by obtaining an infrared thermographic image of the antler and visually ranking the image by comparison to a corresponding image of an antler with the desired composition characteristic.