A Formula for Estimating Surface Area of Dairy Cattle

It has long been accepted as a fact that heat production in the animal body is due to the oxidation processes within the body, and hence is an accurate measure of the rate of metabolism. In order to utilize this standard in research, it becomes necessary to devise a satisfactory method for comparing the heat production of animals of different sizes. Very early in nutritional investigations it became apparent that that the heat production of an animal as not proportional to its live weight. In 1848 Bergmann (3) 3 4 attempted to explain the relatively higher heat production of smaller animals per unit of weight by the generalization that the heat production of the animal body is proportional to its surface area. This idea found wide application and was given strong support by many investigators. Regnault and Reiset (10, p. 514) 5 in their studies of the respiratory exchange of different species under diverse conditions, determined that the oxygen consumption of animals is not proportional to their weight. Obviously the heat production would have a similar ratio per unit of weight, which they explained as being due to the fact that small animals expose a relatively greater surface area to the cooling effect of the atmosphere and consequently require a greater heat production to maintain their body temperature. Some years later Rubner 6 proved that their explanation was faulty, although their general statement of facts was correct. Thus far the idea of the relation between heat production and surface area had been entirely theoretical, since no actual measurements of the surface area of living subjects were available. In 1879 Meeh (8) published the actual measurements of the surface area of living subjects, the results of his own painstaking work, which included the measurements of 6 adults and 10 children. From his measurements Meeh developed a formula by which the surface area of any individual could be determined. This formula