Scientist to investigate methane from deer

01-10-2003 | Not Specified

New Zealand livestock collectively breathe out tonnes of methane each day, but it’s not just cattle and sheep – deer too are contributing to this greenhouse gas problem.

Just how much methane deer produce is the focus of a study being done in the Manawatu by AgResearch scientist Dr Marie Krause, in conjunction with Massey University.

The work is part of a MAF-funded project to build an inventory of methane emissions in New Zealand, which will show very accurately just what our livestock produce over a year.

Measuring methane emissions is the first step in controlling methane production.

With an true picture of methane produced, New Zealand is then in an informed position when it comes to complying with the Kyoto Protocol – the international agreement aimed at lowering greenhouse gas emissions to 1990 levels.

The inventory will also provide a benchmark when new technology and management practices are introduced to control methane production in future years.

While research has been carried out on the methane-producing abilities of sheep and dairy cattle, deer grazing in farm situations have not been looked at before, so Dr Krause’s study is a world-first.

Deer are not generally as passive as sheep and dairy cattle, so it took the scientist some time to train the deer to wear the harnessed yoke needed to collect methane from deer breath over a 24 hour period.

Although only part-way through the trial, studies indicate deer hinds grazing ryegrass produce an average of 22 grams of methane a day, with levels ranging between 14 and 29 grams/day.

This compares with sheep who produce about 23 grams of methane eating up to a kilogram of ryegrass a day.

This is around the level predicted for deer, although Dr Krause would like to carry out further studies to see if young deer produce different levels of methane compared to hinds, and if they produce differently when grazing pasture out of a drought year.

Once deer methane emission figures are finalised, they will be used to calculate emissions over New Zealand’s total deer population.

Dr Krause also predicts the figures will be adopted by other countries in the world needing to calculate their farmed deer methane emissions to comply with the Kyoto Protocol.

More? Dr Marie Krause, AgResearch Grasslands, phone 06-351-8232, email: marie.krause@agresearch.co.nz

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