methane emissions individual dairy cows


Assessment of the methane emission of individual dairy cows at farm house level

Methane emission from dairy cattle accounts for a significant portion of the global CH4 budget which is a substantial contributor to the Global Greenhouse effect. Also as a by-product of microbial fermentation process, methane generation results in about 6-10% loss of the gross energy intake (GEI). In this project we shall design, test and validate an assessment method to determine the methane emission of individual dairy cattle at farm house level. With such a measurement system the variation of the methane emission between a large number of cows can be determined in practice.

Through understanding and evaluating methane emission from individual dairy cattle in large numbers, the methane conversion expressed as the methane emission per unit of milk production can be assessed within the dairy cattle. This information can be used for breeding dairy cattle with low methane conversion which contributes to reducing the environmental impact of dairy farms and increasing the productivity. Besides breeding, also the effect of other mitigation measures can be assessed at animal level, like feeding measures. This project includes following studies: 1) Design and construct the measurement equipment & set-up for methane emission from individual dairy cattle and test under experimental small-scale condition; 2) Evaluate and validate different set-up measurement methods under practical conditions by measurements with real cows; 3) Carry out a proof of principle under practical conditions (up to 50 cows) where methane emission and conversion will be measured during a long period.  Strengths and weaknesses of each method were evaluated what further research should be undertaken to improve the methodology according to measurement requirements at farm level.

In order to explore the level and dynamics in time and space of CH4 and CO2 concentrations at different positions in non-occupied and occupied cubicles, and also analysis the influence from cows, two explorative experiments were done during summer and winter period this year. 9 sampling tubes were installed around the cubicles which CH4 and CO2 concentration can be monitored continuously, and also the behaviour of cows in the cubicles were recorded at the same time. The results of summer experiments were already submitted to the conference of GGAA 2013. In 2013, we will design and test the cubicle measurement method by considering the influence factors from these experiments.