UK - Grazing cattle on hill pasture could be a step towards reducing beef's hefty methane output, providing the system is integrated, say Scottish researchers.
Semi-natural, acidic grasslands yield lower methane emissions from beef cattle than perennnial ryegrass swards, the British Society of Animal Science conference heard yesterday.
This is according to a trial using Limousin cross Aberdeen Angus cattle and native Luing cattle at the SRUC (Scotland’s Rural College).
While breed had no effect on methane output in the study, the influence of sward type was attributed to lower dry matter intake on the hill.
“The lower methane emissions from the hill pasture probably resulted, in part, from lower dry matter intake and forage digestibility,” said Dr John Rooke, a lead researcher on the study.
“Methane adjusted for estimates of dry matter intake and for both DMI and digestibility differed less between sward types than did total daily methane emissions.”
World methane emissions from beef farming account for almost 3 per cent of all human-induced greenhouse gas emissions.
The research was inspired by the fact that beef production has a higher methane footprint than dairy beef due to the “relatively low” output of beef cows, especially when spring calving herds graze on upland pasture.
Practical applications for the findings are there to be exploited if producers are savvy, the SRUC's Dr Jimmy Hyslop told TheCattleSite.
Well run systems could reduce their methane emissions by centring upland grazing periods around the suckling stage, with a new post-weaning site to feature more productive grassland. This was something to bear in mind for those selling calves on.
He acknowledged the trade-off between productivity and methane emissions, stating: “You can use the hills as part of an integrated system. Among other things this depends on the time of year you graze them.”
Government targets demand a 26 per cent reduction in methane emissions by 2020 by 1990 levels. Cattle production accounts for over 60 per cent of methane emission in UK agriculture, the conference heard.
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