Can live weight be used as a proxy for enteric methane emissions from pasture-fed sheep?

• Published in: Scientific reports 2015-12, Vol.5 (1), p.17915-17915, Article 17915
• Main Authors: Moorby, J. M., Fleming, H. R., Theobald, V. J., Fraser, M. D.
• Format: Article
• Language: English
• Subjects: 631/601/1737; 704/158/2456; Animal Feed; Animals; Body Weight; Breeding; Cattle; Digestibility; Dry matter; Emission measurements; Emissions; Grasslands; Humanities and Social Sciences; Methane; Monoculture; multidisciplinary; Pasture; Science; Sheep
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep17915

To test the hypothesis that sheep live weight (LW) could be used to improve enteric methane (CH 4 ) emission calculations, mature ewes of 4 different breeds representative of the UK sheep industry were studied: Welsh Mountain, Scottish Blackface, Welsh Mule and Texel (n = 8 per breed). The ewes were housed and offered ad libitum access to fresh cut pasture of three different types, varying in digestibility: (a) a relatively high digestibility monoculture of perennial ryegrass ( Lolium perenne ), (b) a medium digestibility permanent pasture comprising a range of grass species and (c) a relatively low digestibility native grassland pasture comprising mainly Molinia caerulea . Individual LW, feed dry matter intake (DMI) and CH 4 emissions in chambers were measured. The linear functional relationship between DMI and CH 4 emissions was positive ( r  = 0.77) with little breed effect. The relationships between LW and DMI and LW and CH 4 emissions were also positive but weaker, regardless of pasture type. It is concluded that change to LW was a poor indicator of DMI and has limited value in the prediction of enteric CH 4 emissions from mature ewes.