Improving production efficiency and reducing methane emissions in meat and wool sheep

Summary

A possible option to mitigate methane emissions is to exploit the differences in methane production between individual animals through genetic selection. This strategy could be adopted in extensive grazing systems.

Development of robust protocols to measure a methane phenotype on large numbers of animals is the first step towards establishing the feasibility of reducing methane emissions by genetic selection.

Objectives

This project addressed the following key research questions:

• What is the best method of measurement (protocol for managing animals prior to and during data collection, and number of measurements required including timing of repeat measures)?
• What is the best time to measure an animal - this is essentially a question of whether measures taken at different times in an animal’s life are correlated?

Key findings

• This study suggested that different genetics could be involved in methane production across different diets, but we have not yet sufficient data to derive genetic parameters.
• The estimates of the repeatability of methane production, with or without adjustment for live weight and or feed intake, and across a range of diets and or physiological states, were within the ranges reported elsewhere.
• Methane production varied by almost 2-fold across diets but the effects of pregnancy status on methane production was relatively small.

Benefits to industry

Sheep and cattle produce 60-70% of agricultural greenhouse gas emissions in Australia, and these gases are predominantly methane from rumen fermentation. Reducing methane emissions from livestock is an emerging issue for agriculture and livestock production.

Of the possible options to mitigate methane emissions, exploiting the differences in methane production between individual animals through genetic selection appears to be the most likely strategy that could be adopted in extensive grazing systems.

MLA action

MLA continues to conduct work aiming to develop estimated breeding values and sheep breeding values that will enable producers to select for animals that exhibit low methane traits. The Emissions Avoidance Partnership includes a “Low Methane Livestock” work areas that provides a framework for genetics studies to be undertaken.

Future research

The data collected so far suggest that using feed intake measures along with short term methane measures, although useful, is difficult to interpret and will be difficult to implement in practice so further research is needed. A suitably robust protocol will need to be established for implementation and testing in measurement of many more industry sheep from structured populations.

Related resources

MLA's CN30 overview

Breeding low methane emitting sheep and elucidating the underlying biology, MLA final report, 01 December 2011

Scientific review for B.CCH.1015: Breeding low methane emitting sheep and elucidating the underlying biology, MLA final report, 14 May 2010