The Form Factor of a Cow: Summary

The text below is the summary given in the paper:

Perry, R.L., and Speck, E.P. "Geometric Factors for Thermal Radiation Exchange Between Cows and Their Surroundings", American Society of Agricultural Engineers Paper #59-323.

For evaluating thermal radiant exchange between a cow and her surroundings, the cow can be represented by an equivalent sphere. The height of the equivalent sphere above the floor is 2/3 of the height at the withers. The origin of the sphere is about 1/4 of the withers-to-pin-bone length back of the withers. The sphere size differs for floor and ceiling, side walls, and front and back walls. For the model surveyed, the radius of the equivalent sphere is 2.13 feet for exchange with floor and ceiling, 2.38 feet for side walls, and 2.02 feet for the front and back walls. These values are 1.8, 2.08, and 1.78 times the heart girth. An equation in spherical coordinates is given for the variation of the size of the equivalent sphere with the angle of view measured from the vertical and transverse axes.

The shape factor for exchange with an adjacent cow in a stanchion spacing of 3'8" was found to be 0.1.

Thanks to Nathan Loofbourrow for providing a copy of this paper to me.

Michael Garland

Last modified: Thu Jul 24 13:25:50 EDT 1997