Cool sheep scheme $4.2m baags full

A programme is underway to help reduce greenhouse gas emissions from this country’s sheep flock by encouraging the measurement and uptake of low methane genetics.

In Livestock4 Minutes

THE THREE-YEAR, $4.2 MILLION Cool Sheep Programme aims to offer every sheep farmer access to low-methane genetics and support them to be recognised and rewarded.

Through the programme, stud breeders are being encouraged to have their rams measured for methane emissions with Beef + Lamb New Zealand (B+LNZ) covering the full cost of the process (phenotyping costs) for eligible breeders. The programme is funded by B+LNZ and the Ministry for Primary Industries through the Climate Emergency Response Fund.

B+LNZ’s greenhouse gases and environmental research senior adviser Mark Aspin says the programme will pave the way for the widespread use of lower methane-producing sheep in NZ’s sheep flock.

“This will benefit farmers, the wider industry and the environment.”

Genetic selection for methane requires genotyping and direct measurements (phenotyping) from breeding flocks to accurately generate breeding values.

The breeding values allow rams to be compared and selected to advance the low-methane trait in breeding and commercial sheep flocks.

As part of the project, at least 5000 methane measurements of individual animals will be collected by AgResearch using portable accumulation chambers (PAC) trailers a year.

Aspin says genotyping many of the sires used across the breeding industry will generate breeding values for methane from as many stud and commercial sires as possible.

The programme builds on 12 years of work by AgResearch (funded by the Pastoral Greenhouse Gas Research Consortium and the NZ Agricultural Greenhouse Gas Research Centre). This compared two closed flocks, one low-emitting and one high-emitting under identical management.

Analysis of 20,000 records for maternal traits and 50,000 records for meat traits collected over that time showed clear economic advantages associated with low-emitting sheep.

When compared, using B+LNZ Genetics’ NZ maternal worth index, the low-emitting selection line was found to be about $12 more profitable than the high-emitting line.

“Importantly, the low-emitting sheep showed no adverse effects on health, productivity or profitability while exhibiting leaner growth, improved carcase yield and increased wool production,” Aspin says.

Extensive trials using a range of forages and pelletised rations showed the difference in methane emissions remained constant, irrespective of diet.

The breeding programme, which confirmed that methane emissions were heritable, allowed for the establishment of a breeding value for the trait which has been incorporated into nProve (formerly SIL).

Aspin says the methane breeding value is based on CH4/feed eaten. Not absolute methane produced, as selecting for the latter would favour smaller animals that eat less.

He says methane output is driven by the amount of feed consumed and the goal is to identify animals that use it efficiently. This results in fewer emissions a unit of feed consumed.