Quantification of methane emissions from cattle farms, using the tracer gas dispersion method

In Denmark, agriculture is the largest source of anthropogenic methane emissions (81%), mainly from cattle (dairy and beef) farms. Whole-farm were quantified at nine Danish farms, using tracer gas dispersion method. Five to six measurement campaigns carried out each farm, covering a full year. Of seven home dairy cows two beef cattle. The farms represented typical breeds, housing management systems used in Denmark. emission rates ranged 0.7 28 kg h?1, with highest measurements seen locations number animals. Emissions tended be higher August October, due elevated temperatures high amounts stored manure during this period average factor (EF) for cow was 26 ± 8.5 g Livestock Unit (LU)?1 whereas it 16 4.1 LU?1 h?1 i.e. 38% lower latter. use deep litter house explained some differences found EFs cows. Methane estimated IPCC models national guidelines tended, on all measurements, underestimated by 35% comparison measured emissions, results suggest that future improvements inventory should focus enteric both cattle, especially management.