Short communication: Impact of the intensity of milk production on ammonia and greenhouse gas emissions in Portuguese cattle farms

Abstract

<p>The aim of this study was evaluate the relationship between the intensity of milk production for a wide range of Portuguese commercial cattle farms and NH₃ and greenhouse gas (GHG) emissions from manure management and enteric fermentation. A survey was carried out at 1471 commercial dairy cattle farms (Holstein-Friesian) and the NH₃, N₂O and CH₄ emissions at each stage of manure management were estimated as well as CH₄ losses from enteric fermentation. Gaseous emissions were estimated by a mass flow approach and following the recommendations of IPCC guidelines. The manure management and enteric fermentation in a typical Portuguese cattle farm contributes with 7.5±0.15 g N/L milk produced as NH₃ and 1.2±0.22 kg CO₂ equivalent per litre of milk as GHG. Increasing milk production will significantly reduce NH₃ and GHG emissions per litre of milk produced. It can be concluded that a win-win strategy for reducing NH₃ and GHG emissions from dairy cattle farms will be the increase of milk production on these farms. This goal can be achieved by implementing animal breeding programs and improving feed efficiency in order to increase productivity.</p>