Heat and moisture production in growing-finishing pigs and broilers

Heat and moisture production are important parameters for designing ventilation and climate control systems in livestock housing. In 2002 a report was published of the CIGR Section II Working Group on Climatization of Animal Houses ‘Heat and moisture production at animal and house levels’ with formula to calculate heat and moisture production for different livestock categories. The objective of this paper is to discuss these CIGR formula for growing-finishing pigs and broilers. Results from calculated heat and moisture production with the relatively simple formula in the CIGR report were compared with results from a more comprehensive model. From this comparison the following conclusions were drawn: 1) The relatively simple CIGR formula to calculate total heat production of growing-finishing pigs give similar results as the comprehensive model in which protein and fat retention are calculated, and seems therefore sufficient accurate. Only the table to calculate metabolizable energy needs to be updated, because of genetic improvement of the pigs in the last decades. 2) To calculate total heat production for growing-finishing pigs a linear correction factor is used for indoor temperature. Although this does not fit with the concept of a thermo-neutral zone, this could be done without large error. 3) Calculation of moisture production in growing-finishing pigs can be improved by separating moisture production from the pigs and moisture production from the rest of the house. This, more fundamental approach for determining moisture production, is needed to be able to accurately calculate moisture production under less average conditions. 4) The CIGR equation to calculate total heat production of broilers is too simple, while it is not related to the main variable determining heat production, the ME intake. 5) The CIGR formula to calculate moisture production of broilers should not only depend on indoor temperature, but also on live weight of the birds. Similar as for pigs, it is also suggested to separate moisture production from the animals and moisture production from the rest of the house