|
DCA Publikationer Implementation of the use of the enteric methane mitigating feed additive Bovaer® in the national danish emission inventories for Dairy Cows DCA rapport, nr. 229, 2024 Af Peter Lund, Morten Maigaard, Maria Holst Kjeldsen, Marianne Johansen, Anne Louise Frydendahl Hellwing, Martin Riis Weisbjerg & Ole-Kenneth Nielsen  Use of feed additives that can mitigate enteric methane from ruminants is a promising technology. This calls for the inclusion of the effect of such feed additives in National Emission Inventories. 3-nitrooxypropanol (3-NOP) is the active component in Bovaer®. The product has been shown to reduce enteric methane yield from dairy cows, but with quite pronounced differences in reduction potential between doses and nutrient composition of rations. The aim of this peer-reviewed report is to provide the scientific evidence for including the use of Bovaer® in the calculation of the emission factor for dairy cows in the Danish National Emission Inventories for Agriculture. An average reduction potential of 27 % in methane yield (g methane/kg of feed dry matter) is expected based on inclusion of national activity data in a prediction model based on a recently published meta-analysis, when a dose of 60 mg 3-NOP/kg feed dry matter is used in Danish diets for dairy cows. This reduction potential is aligned with the average predicted and average observed reductions in methane yield from experiments performed at Aarhus University with dairy cows fed a dose of 60 mg 3-NOP/kg feed dry matter and with the outcome of experiments in other parts of Northwestern Europe, but is slightly lower than the average reduction potential observed on commercial farms. This reduction potential can subsequently be incorporated when calculating the emission factor for enteric methane from dairy cows, if reliable activity data for the use of Bovaer can be provided. |