Features of a new calorimetry unit to measure heat production and net energy by group-housed pigs

The Swine Calorimeter Unit (SCU) has been constructed at the University of Illinois at Urbana-Champaign. The objective of the SCU is to be able to determine net energy (NE) of diets and ingredients fed on an ad-libitum basis to group-housed pigs in all phases of production. The SCU allows for calculating NE based on the indirect calorimetry procedure. There are 6 calorimetry chambers in the SCU. Each chamber is made air-tight, and measures 1.8×2.0×2.7 m, has fully slatted floors, and a volume of 10.2 m3, with a capacity to hold 4 to 10 growing-finishing pigs depending on size. There are 4 manure screens and 2 urine pans under the slatted floors. Each chamber is equipped with a fresh air supply system. A regulator unit controls humidity and temperature in each chamber. The ‘classic line system’ developed by Sable Systems International is used to measure gas exchanges in the chambers. Methane, carbon dioxide, and oxygen gases are masured in a determined period and are reported in percentage units. The initial objectives include comparisons of net energy in individually housed and group-housed pigs.