Three methods for the calculation of the ventilation rate in Northern European livestock buildings were compared on the basis of the balances of animal heat, moisture and carbon dioxide for fattening pigs, dairy cattle and laying hens. The analyses were made on data sets from a collaborative project using literature values for the rates of production of heat, moisture and carbon dioxide. For heat and moisture production, it was found that the balance equations could be improved by including a correction for evaporation of water from fresh food, faeces and urine in livestock buildings, and by adjustment of the equations for partitioning total heat into sensible and latent heat for pigs and poultry. The correction, which is valid for climatic regions and production schemes that exist in Northern Europe, was calculated for each building in such a way that the heat and moisture balances
gave the same ventilation rate. The three methods gave reliable results on a 24 h basis, except when there were small hourly diA