title: Methane emission by adult ostriches (Struthio camelus).
abstract: Ostriches (Struthio camelus) are herbivorous birds with a digestive physiology that shares several similarities with that of herbivorous mammals. Previous reports, however, claimed a very low methane emission from ostriches, which would be clearly different from mammals. If this could be confirmed, ostrich meat would represent a very attractive alternative to ruminant-and generally mammalian-meat by representing a particularly low-emission agricultural form of production. We individually measured, by chamber respirometry, the amount of oxygen consumed as well as carbon dioxide and methane emitted from six adult ostriches (body mass 108.3±8.3 kg) during a 24-hour period when fed a pelleted lucerne diet. While oxygen consumption was in the range of values previously reported for ostriches, supporting the validity of our experimental setup, methane production was, at 17.5±3.2 L d(-1), much higher than previously reported for this species, and was of the magnitude expected for similar-sized, nonruminant mammalian herbivores. These results suggest that methane emission is similar between ostriches and nonruminant mammalian herbivores and that the environmental burden of these animals is comparable. The findings furthermore indicate that it appears justified to use currently available scaling equations for methane production of nonruminant mammals in paleo-reconstructions of methane production of herbivorous dinosaurs.
authors.affiliation: Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Switzerland.
authors.forename: Samuel
authors.initials: S
authors.lastname: Frei
authors.affiliation: Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Switzerland; ETH Zurich, Institute of Agricultural Sciences, Zurich, Switzerland.
authors.forename: Marie T
authors.initials: MT
authors.lastname: Dittmann
authors.affiliation: Reutlingers Straussenfarm, Rikon, Switzerland.
authors.forename: Christoph
authors.initials: C
authors.lastname: Reutlinger
authors.affiliation: Leibniz Institute for Zoo and Wildlife Research (IZW) Berlin, Germany.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Ortmann
authors.affiliation: Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Switzerland.
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Hatt
authors.affiliation: ETH Zurich, Institute of Agricultural Sciences, Zurich, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Kreuzer
authors.affiliation: Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Switzerland. Electronic address: mclauss@veclinics.uzh.ch.
authors.forename: Marcus
authors.initials: M
authors.lastname: Clauss
mesh_terms: D000821:Animal Feed; D000818:Animals; D004068:Digestive System Physiological Phenomena; D008322:Mammals / Q000502:physiology; D008697:Methane / Q000378:metabolism*; D020310:Struthioniformes / Q000378:metabolism / Q000502:physiology*
chemical_list: D008697:Methane
keywords: Digestion; Fermentation; Herbivory; Methanogenesis; Ratites