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The population of sheep in New Zealand currently sits at around 43.1 million. They double the number of cows and yet have a better environmental reputation. What springs to mind when you hear natterings of a fart tax? Yes, Dairy farms. Sheep, on the other hand, are a bit overlooked by the general population, but not to those at AgResearch Invermay, just outside of Mosgiel. In fact, for the past two years, Dr John McEwan and his colleagues have been investigating the production of Greenhouse Gases (GHGs) such as methane in ruminant ovine (sheep) populations with funding from the Pastoral Greenhouse gas Research Consortium and the New Zealand Agricultural Greenhouse gas Research Centre. Georgie Fenwicke talked to him about his research, past and present, in the area.

So just to start off, can you describe what effect the production of methane in sheep and cattle has on the environment?
As far as, a lot of greenhouse gas production in New Zealand comes from ruminant production of methane. I can't remember the exact figures, but I think something around 54% comes from ruminant animals and the ruminant industry. My work is just associated with animal variations of methane emissions.
 
What is the science behind the research you are currently working on into breeding low methane producing sheep?
With our work we have two main aims: the first is to try and find how big that variation is, how consistent it is and what proportion is related to the genetics of the animal itself rather than the bugs in the rumen, because the methane is actually produced by the bugs in the rumen, not by the animal. So it is indirect, it is how the animal is controlling the bugs in the rumen that produce the methane.
 
The second part, assuming that this variation has a genetic component, is how it is related to the traits people look for in sheep and cattle at the moment. So how is it related to weight, wool production, to the number of lambs born and a number of other traits?
 
Another aim you have had was to create a faster, cheaper way of obtaining these estimates. How is that going?
In our research all we really need to do for breeding is to rank the animals; we don't need to know what the actual readings are. We just need to know which is better than that one with a reasonable degree of reliability. One of the things we have been looking at is instead of measuring over a whole day measuring over a shorter period and looking at what sort of results we can get to rank the animals.
 
The short answer is that measurements over a short period of about an hour are pretty reasonable under some circumstances and that potentially offers a cheaper way of measuring more animals.
 
If developed, how will your research be distributed? Will it be taken to market, or given to farmers to work with?
If we have got animals who have got high methane emissions and animals that have got low methane emissions, what we can do is we can go and see what is causing those differences from a metabolic or a microbial scenario. If we understand that, there may be other ways of altering methane emissions that are nothing to do with breeding animals. In one way, we are creating a research tool. We know that there is individual variation between animals so let's see what is causing it. If we understand that process, there are all sorts of possibilities that it could be changed.
 
If we go down the breeding line - if methane emissions are genetically variable in animals - then, we could do it directly using a rapid sheep measurement for methane. That is one possibility, probably in a central facility. But another possibility is using what are called SNP (Single Nucleotide Polymorphisms) chips, which basically measure many thousands of DNA variations across the genome. Another possibility is that we could train these SNP chips on animals, so that we have measured and simply genetise animals and make predictions of their difference in methane production.
 
You were instrumental in the development of these SNP chips. How were they developed?
I was a part of a core group that sequenced, in this particular case, the sheep genome. Based on the information we got, we selected a bunch of SNP’s which were equally spaced across the genome and quite polymorphic, and we worked with a company called Illumina to make a SNP chip. Those SNP chips are being widely used around the world now.
 
On a personal note, you graduated with a Bachelor of Science from Otago in Biochemistry; what led you into the field of sheep and cattle genetics?
I came from a farm down in Southland, right down in a place called Tokanui, where Jamie Mackintosh the Captain of the Southland rugby team comes from. On our farm, we had a stud sheep flock so I was obviously bought up with farming, and I then went off and did what was then a rather novel degree in Biochemistry at Otago. At that time there weren't many jobs and most people went overseas straightaway. I don't know, after about eighteen months or two years, I finished up working on a research station down there that is now part of AgResearch and I have been here ever since.
 
Where to from here?
In this research we are doing at the moment, we have got some interesting results, but there is no indication that we will be able to apply it economically to the industry. We are proceeding down the path and by the end of the year we will probably be in a reasonable position to see where this research will be and where we will need to go to from there.
 
So we should expect some sort of announcement next year?
Hopefully.
 
In saying that there is no absolute certainty that you will be able to apply it economically to the industry, I couldn't help but notice that many of the companies funding the PGgRC are names such as Fonterra and PGG Wrightson. Do you think they will have an effect on being able to apply it?
Companies in New Zealand such as Agriculture New Zealand and Fonterra are funding it because Greenhouse gases are of vital importance to their industries long term; to try and reduce emissions. Like all research they are funding it in the knowledge that if they invest in the area, one or more of the approaches will come up with something useful.