Modelling heat production and heat loss in growing-finishing pigs

The objective of this paper is to discuss some aspects of modelling heat production and heat losses in growing-finishing pigs. The main formulas from an existing, continuously updated, model (Anipro) are compared with existing formulas given by the CIGR working group on Climatization of Animal Houses (2002) and other formulas described in literature. The main conclusions from this comparison are: 1) the estimates of the metabolizable energy for maintenance varies substantially between different studies; this seems to be related to differences in animal activity levels during the studies and differences in genetics of the pigs; 2) the CIGR formulas for calculating heat production seems to be valid for modern pigs; the feeding levels, however, defined as n times maintenance, should be updated; 3) the Anipro and CIGR formulas for calculating evaporative heat losses are too simple and should be updated with a more fundamental approach, including not only ambient temperature, but also humidity level, respiration volume of the pigs, wetted areas inside the house, and air velocity.<br/>Keywords: pig