SREL Reprint #2241

Evaluation of the cyclopropane absorption method of measuring avian body fat

James A. Gessaman1, Roy D. Nagle2, and Justin D. Congdon2

1Department of Biology and Ecology Center, Utah State University, Logan, Utah 84322, USA
2Savannah River Ecology Laboratory, Drawer E, Aiken, South Carolina 29802, USA

Abstract: The mean absolute percent error of predicting the fat mass of 40 Rock Doves (Columba livia) by the cyclopropane absorption method was 11%. A sensitivity analysis of some of the 15 variables used in computing fat mass by the cyclopropane absorption method showed that: (1) cloacal temperature was a good measure of body-fat temperature, (2) the lipid solubility coefficient of cyclopropane reported for rats was appropriate for pigeons, (3) minimum error occurred with an animal density of 1.08, (4) error was relatively insensitive to a range of reasonable estimates of body water, and (5) the most accurate method of measuring chamber volume was unclear. We list advantages and disadvantages of this user-unfriendly method and provide recommendations for future users. This method does not require a calibration based on fat extracted from dead birds; the accuracy and precision of a system assembled to measure the fat mass of live birds can be evaluated with olive oil standards. The accuracy of estimating fat mass of a living bird seems to be dictated, in large part, by the analytical equipment and procedures used rather than by the bird.

SREL Reprint #2241

Gessaman, J.A., R.D. Nagle, and J.D. Congdon. 1998. Evaluation of the cyclopropane absorption method of measuring avian body fat. The Auk 115:175-187.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).