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This Article Full Text Full Text (PDF) All Versions of this Article: jas.2007-0373v1 86/2/384    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Christophersen, C. T. Articles by Vercoe, P. E. Search for Related Content PubMed PubMed Citation Articles by Christophersen, C. T. Articles by Vercoe, P. E.

In vitro methane emission and acetate:propionate ratio are decreased when artificial stimulation of the rumen wall is combined with increasing grain diets in sheep¹

C. T. Christophersen^*,,2,3, A-D. G. Wright^,4 and P. E. Vercoe^*

^* University of Western Australia, Faculty of Natural and Agricultural Sciences, Crawley, Western Australia 6009, Australia; and and Commonwealth Scientific and Industrial Research Organisation Livestock Industries, Centre for Environment and Life Sciences, Private Bag 5, Wembley, Western Australia 6913, Australia

³ Corresponding author: c.christophersen{at}csiro.au

The interaction of retention time in the rumen and concentrate diet on methane production in vitro and acetate:propionate ratio was examined. Twenty-four fistulated sheep were used in a complete factorial design with the sheep randomly divided into 4 groups. The sheep had a 5-wk acclimatization period on an oaten chaff diet, followed by two 3-wk diet phases. Two of the 4 groups were maintained on the oaten chaff diet for the duration of the experiment, with pot scrubbers added to the rumen of 1 of the 2 groups. The remaining 2 groups were offered a low-grain diet (35% grain) in the first diet phase followed by a high-grain diet (70% grain) in the second diet phase. Pot scrubbers were also added to the rumen of 1 of these 2 groups of grain-fed sheep. Pot scrubbers in combination with a low-grain diet decreased the amount of methane produced in vitro from 4.25 to 3.71 mmol/mL of digesta when compared with oaten chaff-fed sheep without pot scrubbers (P < 0.05). The acetate:propionate ratio was 1.6 in sheep fed a high-grain diet with pot scrubbers compared with 2.4 in sheep fed a high-grain diet without pot scrubbers in their rumen (P < 0.05). At high levels of grain, when employing a multivariate statistical analysis including all data, sheep given the combined treatment of grain and pot scrubbers were different from all other sheep groups in this experiment (P < 0.05). Furthermore, sheep fed a high-grain diet were different from sheep receiving the oaten chaff diets with and without pot scrubbers (P < 0.01 and P < 0.05, respectively). In conclusion, pot scrubbers combined with grain alter the rumen fermentation, and introducing pot scrubbers into the rumens of livestock consuming low levels of grain may be a way to lower methane emissions.

Key Words: acetate:propionate ratio • methane • methanogen • pH • sheep • volatile fatty acid