Adapting feeding methods for less nitrogen pollution from pig and dairy cattle farming: abatement costs and uncertainties

Abstract

This study assesses abatement costs of three measures aimed at reducing nitrogen (N) emissions from livestock production: two protein-adjusted feeding strategies for pigs, and higher-quality forage for dairy cattle. In a partial cost approach, we quantified the effect of different measures on N losses and production costs. We accounted for emissions of NH3, N2O and NO from animal housing, manure storage, manure application, and from soils. Uncertainties related to volatile prices and assumptions about excretion rates and emission factors were assessed in a Monte Carlo simulation. Covering variability of individual input parameters, this uncertainty assessment addresses a fundamental gap in current decision support on N loss reduction measures. For the scenarios investigated, average N abatement costs at farm level were negative and represented net benefits to farmers: In pig husbandry, adapting feeding practices in most individual situations resulted in net benefits, both for three-phase feeding (min −35, max +5, mean −14 €/kg N abated) and optimised single-phase feeding (min −52, max +4, mean −21 €/kg N abated). In dairy production, N abatement by improved forage quality proved invariably more economic than current practice (min −40, max −11, mean −21 €/kg N abated). As shown in this study, N abatement costs can serve as a framework for comparing the cost-effectiveness and feasibility of N loss reduction measures within and between livestock production systems. This is in turn critical when informing practitioners and providing policy support on workable strategies for reducing the N footprint of animal husbandry.