Hello, everybody. My name is Cristhiam Munoz. I am a second year master’s student under Dr. Hans
Stein, and today I will be describing the new calorimetry unit from our monogastric nutrition
laboratory. The Swine Calorimeter Unit, or SCU, is located at the Swine Research Center at the
University of Illinois at Urbana-Champaign. It was built with the objective of determining net
energy in group housed pigs and to test the hypothesis that the net energy from individually housed
pigs is greater than from group housed pigs. The SCU allows the calculation of net energy, or NE,
based on the indirect calorimetry approach, which estimates total heat production from the gas
exchange produced by the animal in the respiration process. In this method, the amount of oxygen
consumption and the amount of carbon dioxide and methane produced are related in a prediction
equation to estimate heat production, or HP as is shown in Figure 1. This equation is corrected by
urine nitrogen excretion. In Figure 2, we can observe a photo of the outside of the calorimeter. The
SCU measures 28 meters long, 5 meters wide and 3 meters high. Figure 3 is showing the plan of the
inside of the SCU, which consists of a feed storage room, an access corridor, three equipment rooms,
six calorimetry chambers, a computer room and a mechanical room. To give more details about the
procedure to estimate net energy, I want to bring your attention to Figure 1. Here we observe a
scheme of a calorimetry chamber and the equipment room. The calorimetry chamber is composed of a
main chamber for animal allocation and a secondary chamber to collect total, but separate, feces and
urine. Fecal and urine collection allows for the calculation of digestible energy (DE) and
metabolizable energy (ME) respectively. In the equipment room, the air handling equipment for two
chambers is located. This equipment includes systems to supply fresh air to control temperature and
relative humidity and to analyze air samples for oxygen (O2), carbon dioxide (CO2), and methane
(CH4). These readings are sent to the master computer located in the computer room, where the value
of heat production is determined. Finally, having the values for DE, ME, and HP, net energy is
obtained.

Here, we are looking at the chamber features. Each chamber has an airtight door and contains one
wet/dry feeder with a capacity of 35 kilograms and an auxiliary drinker to ensure ad libitum access
to water. One chamber can accommodate four to ten growing-finishing pigs depending on the size. The
secondary chamber has four flat screens and two pans for feces and urine collection. In each chamber
room, two fresh air supply systems are placed. The systems provide clean air for the air exchange
into the chamber and provide the baseline level for the gas analyzers. The fresh air exchange system
consists of a centrifugal inline fan and an AccuValve. The valve has an accuracy of plus or minus
5%. The chamber pressure is regulated by a manual rotatory plate valve located in the exhaust tube.
The chamber temperature can be controlled with an accuracy of plus or minus 0.1 degrees Celsius and
plus or minus 0.5 percent for relative humidity; this level of precision is ensured by the use of
the dew point control system. The rate maximum heat of rejection for each unit is approximately
7,300 watts per hour. The gas analyzer system provides readings of O2, CO2, and CH4 for a subsample
taken from the chamber return duct. The readings are provided in percentage units within a high
resolution. The swine calorimeter unit will start operating in the summer of the current year—stay
tuned for new updates. 

Thank you for your attention and if you want to learn more about this or other topics, please visit
our website at nutrition.ansci.illinois.edu.