Climate-Smart Cattle Breeding project update: interview with Anouk van Breukelen

The Climate-Smart Cattle Breeding project (LWV19155) focused on large scale phenotyping to enable selective breeding as a methane mitigation strategy. The project started in 2020 as an expansion of an earlier pilot project in the Integral Approach programme of LNV. The Climate-Smart Cattle Breeding project was co-funded by CRV and Friesland Campina, and is coming to a close in 2024. Now is the time to look back and reflect on lessons learned, and recognise the hard work and dedication of the people involved in this project.    

Anouk van Breukelen, one of the PhD candidates at Animal Breeding and Genomics (ABG), has been involved in the project from the very beginning. “I was hired as a PhD on this project because I already had some experience with using sensors to measure individual methane emissions of cows,” she says. “This was for the Integral Approach project where we also used sensors to measure methane and CO2 in the milking robots on dairy farms on a smaller scale.”

Sniffers for accurate methane measurements

To measure individual methane emissions, Anouk and her fellow scientists used so-called ‘sniffers’. In methane sniffing, sensors detect methane using in situ emission measurements. Air samples are brought to a sensor, and the results are analysed using carefully developed models. The sensors used in the Climate-Smart Cattle Breeding project are improved versions of the ones used in the Integral Approach project.

“In the past, the most common method to measure cows’ individual methane emissions was in respiration chambers,” says Anouk. “But if you need information on a lot of cows, that’s just not feasible, not when you have to record thousands of animals for selective breeding. Over the last few decades there have been quite some developments in different methods to phenotype methane that are more cost-effective and less labour-intensive, and the sniffers we used are a promising and cost-effective method in measuring emissions.”

Lots of data

Anouk and her colleagues used the sniffers to collect data on individual methane phenotypes, which proved to be a significant undertaking. “We needed a lot of data,” says Anouk. “In fact, collecting all the data was probably the largest part of the project. Right now, we’ve finished collecting data at approximately 70 dairy farms, but we’re aiming at 100 farms in total (each with approximately 150 cows, ed.). We’re a bit behind on schedule, but that’s mainly because the sensors we’re using need more maintenance than we anticipated. It will probably take a few more months before we can present all the end results of this project, but so far we have been able to use the data to develop models and publish the first results on the data we have collected up to this point.

Establishing the impact of selection

The Climate-Smart Cattle Breeding project focused on four main areas: 1) Extensive and automated recording of methane emissions per cow (which is where the sniffers came in), 2) Breeding value estimation models, 3) Knowledge of the impact of selecting cows with lower emission levels (and other characteristics), and 4) Implementation in practical and widely accepted tools.

“We have used the cow phenotypes to estimate genetic parameters, heritabilities and genetic relations with other traits. That information will soon be put into the new breeding goal or selection index that CRV is currently developing with the data from the project,” says Anouk. “But to be able to incorporate methane in a breeding goal, we need to look at the relationship with other traits as well; if we select cows for lower methane emissions, how will that affect other traits? What will it do to the cows’ milk yield or fertility? We’re aiming for balanced breeding, so we need to make sure that breeding for low methane won’t have a negative effect on other traits. There are definitely some questions there, and I’m currently working on those analyses for my final paper.”

Practical implementation

“Practical implementation of our research is very important,” says Anouk. “We’ve always kept close contact with the farmers that were involved in the project and organized several meetings where they could meet and where we shared results of our research. They all seem very enthusiastic about the project, which is really stimulating! To encourage the uptake of new breeding tools across the Dutch farmer communities and their participation in the breeding programmes, we’re currently trying to implement our results in the Kringloopwijzer. The Kringloopwijzer is a tool used by farmers to keep track of all their emissions. It already has a general value for methane, but this value is based on the total number of cattle on the farm. If, for example, there’s a herd with a low-methane output, you can’t tell it apart from a herd with high-methane output. You don’t see the difference between individual cows. That’s something that we want to change.”