N-Efficacy in fattening pigs

In regions with high density of animal production, Import/Export-balances (IMPEX) are used to monitor the use of diets with reduced P- and N- concentrations. Based on the IMPEX data, the farms can claim a reduction in waste nutrients. The aim of the presentment study was to analyze 1665 IMPEX-balances from pig farms in the state of Lucerne (Switzerland). All data were from 2008. The data from 899 grower/finisher farms were analyzed in more detail and N-efficiencies (N-Export/N-import) estimated. The average N-efficiency for grower/finisher farms was 32 % with an average dietary crude protein (CP) concentration of 159 g/kg (13,74 MJ DE). The between farm comparison showed a large farm effect on both, N-efficiency and N-output as manure. Only a minor portion of this variation could be explained by feeding strategy. The data suggest that a large optimization potential for N-efficiency exists with respect to production technique, animal health and overall farm management. The N-efficiency in grower/finisher farm is a good indicator for the evaluation of good farm practices. However, in farrowto finish operations, it is very difficult to evaluate the N-efficiency for different production phases.