Excretion calculation of pigs in Finland : ERITYS-project report

The official excretion calculations provide the amounts of dry matter, organic matter and nutrients excreted in faeces and urine by different livestock species and categories. Natural Resources Institute Finland (Luke) is responsible for the national excretion calculations in Finland. The results of the calculations are used e.g. in estimating emissions during manure management and use into air (greenhouse gases, ammonia) and waters [phosphorus (P), nitrogen (N)], in estimating the quantity and composition of manure produced in Finland and in setting the targets to improve manure utilisation (nutrient balances, circular economy). The calculations and their results can also be used in manure-related life cycle assessments (LCA) and in practical steering of livestock production e.g. during environmental permitting involving manure storage capacity and sufficient field area for spreading manure. The amounts of nutrients excreted are calculated as the difference between nutrient intake in feeds and nutrients retained in the animals and their products. The components included in the calculations are dry matter, organic matter, N and P. The excretion calculations of pigs are conducted separately for different animal categories based on their weight and type of production (breeding, piglet production, meat production). The critical factor of nutrient excretion calculations is to accurately estimate the amounts and nutrient concentrations of feeds consumed by the animals. For the calculations, this was obtained by estimating the energy requirement of the animals according to the published Finnish feeding recommendations (taking into account production phase, amounts of piglet production and growth rate). The diet composition was based on field data and expert assessments. There is much less uncertainty in estimating the intake of nutrients than in the amounts of nutrients retained in the animals themselves. The detailed steps in the calculations are described in the report. Based on the results with year 2023 as an example, the annual N and P excretions of one fattening pig place were 13.5 and 2.55 kg, respectively. For a sow place (sow and piglets before weaning), the annual N and P excretions were 21.1 and 5.54 kg, respectively.