Friday, December 8, 2023

Breeding value targets methane

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Beef + Lamb Genetics has launched a low methane breeding value tool so sheep farmers can breed stock that emit less of the greenhouse gas.
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Farmers will have access to rams within two years – the time it will take to breed and grow rams on a commercial scale.

Till now the only option for farmers wanting to cut greenhouse gas emissions has been to constantly improve their overall farming efficiency, Pastoral Greenhouse Gas Research Consortium general manager Mark Aspin said.

“This takes us a step further – towards actually lowering sheep methane emissions in keeping with the sector’s commitment to work towards reducing its greenhouse emissions.”

Though progress through breeding can be slow – about 1% a year assuming a breeder selects only for methane – it is cumulative.

Ram breeders wanting to tap into the methane breeding value will need to measure some of their flock using a portable accumulation chamber.

The chambers are on an AgResearch trailer that goes to farms. Sheep spend 50 minutes in the chambers where their emissions are measured. Measurements are taken twice, at a 14-day interval, and the data collected is used alongside other genetic information to calculate a methane breeding value.

King Country stud breeder Russell Proffit, whose family has been producing rams for 40 years, had 84 rams measured in September.

He decided to measure for methane BVs because he believes an animal that is healthy and doing well should produce less methane and he wanted to test for that.

“I don’t know if that’s the case yet but, either way, breeding for less methane complements what we are working to achieve on our stud. That is more robust rams that require less inputs and make less demand on the environment.”

Proffit breeds for facial eczema tolerance and hopes there is a link between sheep producing less methane and being more tolerant to FE. That’s yet to be determined.

He posted a video on the Raupuha Stud facebook page of his sheep being measured, which generated a fair bit of interest from farmers who got in touch to find out more.

Research shows breeding for low methane produces sheep with smaller rumens that lead to shorter, more frequent feeding.

The question, yet to be answered, is what impact that will have on ewes during peak lactation.

Aspin says those involved in the programme are well aware that, given a choice, farmers will choose to select for feeding efficiency rather than methane if it involves a significant compromise.

There have been some indications breeding for less methane emissions might also provide a small increase in parasite resistance.

The biggest influence on methane emissions is the amount of feed an animal eats, he says. 

“To that end, the consortium is working on another three technologies with a focus on reducing the amount of methane generated by feed. So, by breeding sheep that produce less methane per mouthful eaten – as other methane-reducing technologies come on stream – the influence of these sheep on the national flock’s methane production becomes compounding.”

Those other technologies include research into types of feed that could reduce methane emissions and targeting the methanogens in the rumen through inhibitors and vaccines.

The feed research is focused on crops because it is very difficult to get a reduction in nitrogen outflow from the pasture that is the basis of NZ farming systems.

A diet of brassica rape can cut methane emissions by up to a quarter but fodder beet offers other challenges that need to be dealt with.

One the vaccine side work done so far has found ways to reduce methanogens in laboratory tests but they are yet to be repeated in the rumen during trials.

An Agricultural Greenhouse Gas Research Centre report said three sheep vaccination trials did not reduce methane emissions.

However, new vaccine antigens have been identified and are being investigated in the laboratory to refine them before testing them in animal trials.

The report says the methane inhibitor programme is developing compounds that reduce methane by 20-30% and they can be fed to grazing livestock. Discussions are under way with commercial companies about the potential delivery of the inhibitors to farmers in NZ and overseas.

Aspin says once the tools are developed further testing will determine whether they will work together to produce a combined effect or whether they target the same methane-producing mechanisms.

Results from the sheep breeding programme have also led to the establishment of a NZ Dairy Genetics working group to develop breeding options for low-methane cattle.

Based on a review of genetic programmes internationally it was decided to test the efficacy of using a C-Lock GreenFeed system to identify low-emitting phenotypes.

A trial will begin early next year.

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