B13 Global Methane Genetics Initiative (BO-43.10-002-054)

Sniffers from various manufactures are widely recognized instruments to measure methane (CH₄) and carbon dioxide (CO₂) emissions in the breath of ruminants during milking or feeding. Breath-sampling techniques are non-invasive – once installed in e.g. an automatic milking system, animals are not aware of the equipment. Sniffers are also relatively cheap compared to other methods like GreenFeed and Respiration Chambers (including portable ones). In dairy cattle, sniffers are widely used as the method of choice to phenotype substantial numbers of cows long-term as they are easily adapted to automatic milking systems (AMS). Sniffers can be attached to either one or several AMS at the time, switching among them to measure CH₄ and CO₂. However, there is a lack of standardization between manufactures and protocols in terms of methods of calibration and utilization of the equipment at a farm level. In addition, the type of installation (such as various AMS-based and AMS-free installation) will affect the gas retrieval.

Moreover, a standardization across countries is relevant for data processing techniques (which cover measurement system faults detection, data synchronization, measurement noise filtering, etc. of raw gas data) allowing the recorded methane data to be ready for defining phenotypes for genetic evaluation in an efficient way. Until now, countries have been doing all these efforts by themselves, not sharing data or protocols which make these tasks more challenging. Likewise, many phenotypes have been suggested, but there are no standards on how to form these either. Merging databases where data were collected and processed and phenotypes formed using different methods and protocols, might lead to poor (statistically unreliable) estimates for parameters such as heritability and genetic correlations.

Currently, sharing most historical data among countries is complicated by complex data sharing agreements, policies and data ownerships. However, sharing data among countries is needed to accelerate the genetic progress of reducing methane emissions in dairy cattle. This project will focus on defining and establishing the protocols to install and calibrate sniffers, as well as to align, clean, and process the sensor raw data until its final phenotype.

The project will also focus on collecting phenotypes to stimulate the international collaboration by i) sharing of data through the Global Methane Genetics initiative; ii) developing a model for genetic evaluation across more countries; and iii) investigating how breeding values from this evaluation can be implemented as a tool for climate gas reduction in the credit system at farm level as well as national level. Therefore, standardizing data collected from different countries guarantees uniformity and consistency regarding data format, phenotype measurement and data quality. Breeding values for methane allow farmers to selectively breed animals with reduced methane emission, but also serves as an important component within climate accounting systems to quantify environmental footprint of livestock production and incentivize sustainable breeding practices at the farm level while aligning with national environmental goals.