Effect of Postural Position and Position Changes on Energy Expenditure in Fasting Dairy Cattle

Abstract

Four Holstein steers approximately 2 years of age were used to measure the fasting expenditure of cattle while standing, lying, and during position change (standing up or lying down). Thirty-two 10-hour periods of fasting heat production were studied during which energy expended in postural changes was measured. An open-circuit mask technique was used to collect air expired by the animal. The small volume of the mask made possible immediate detection of changes in gas concentrations due to postural changes. The O2, CO2, and CH4 concentrations in expired air were monitored continuously during the periods by electronic gas analyzers, and recorded by a multi-channel recorder, along with rate of air flow through the mask and body position. These data then were separated so that the energy expended while standing, lying, and during position change could be calculated. Results of this experiment did not support the factors presently being used to correct for activity during heat production measurements. A new method of correcting for activity was proposed; activity is corrected to a defined standard day. For each double change in body position different from the number prescribed in a standard day a factor ± .195 kcal/kg W.75 is added to the total heat production. The mean correction factor for excessive time spent standing or lying was 13.5% of the mean hourly heat production but varied with the length of time to be corrected. © 1972, American Dairy Science Association. All rights reserved.