|FOTH, ALISON - University Of Nebraska|
|Brown Brandl, Tami|
|KONONOFF, PAUL - University Of Nebraska|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 3/7/2013
Publication Date: 7/1/2013
Citation: Foth, A.J., Brown Brandl, T.M., Freetly, H.C., Hayes, M., Kononoff, P.J. 2013. Validation and recovery rates of an indirect calorimetry headbox system used to measure heat production of cattle [abstract]. Journal of Animal Science. 91(E-Supplement 2):262.
Technical Abstract: A headbox system was constructed at the University of Nebraska-Lincoln to determine heat production from dairy cattle using indirect calorimetry. The system was designed for use in a tie-stall barn to allow the animal to be comfortable and was mounted on wheels to transport between animals between sampling days. The frame was constructed out of aluminum angle iron with sides of plexiglass for other animals to remain within sight. The system continuously sampled gas produced in the headbox and directed it into foil bags, allowing for analysis of O**2**, CO**2** and methane concentrations. To validate the data collected by three constructed units, alcohol burning lamps containing 100% ethyl alcohol were placed inside, ignited and burned for 2 h. The rate of gas flowing out of the system was recorded and samples of gas entering and exiting each of the sealed headboxes was collected into 44 L sample bags and later analyzed. The difference between gas concentrations from incoming and outgoing air, corrected to standard temperature and pressure, was calculated and the amount of O**2** consumed and CO**2** produced during the sampling time was compared to the theoretical amount of each of these gases calculated based upon the amount of alcohol burned, giving the recovery rate of each gas. Two runs were carried out on two separate occasions for each unit and the results can be found in Table 1. Recovery rates for O**2** and CO**2** averaged 101.3±2.72% and 100.5±3.59% suggesting that these units may be used to adequately estimate gas exchange and for indirect calorimetry to indirectly determine heat production.