Methane emission by camelids.
Methane emissions from ruminant livestock have been intensively studied in order to reduce contribution to the greenhouse effect. Ruminants were found to produce more enteric methane than other mammalian herbivores. As camelids share some features of their digestive anatomy and physiology with ruminants, it has been proposed that they produce similar amounts of methane per unit of body mass. This is of special relevance for countrywide greenhouse gas budgets of countries that harbor large populations of camelids like Australia. However, hardly any quantitative methane emission measurements have been performed in camelids. In order to fill this gap, we carried out respiration chamber measurements with three camelid species (Vicugna pacos, Lama glama, Camelus bactrianus; n = 16 in total), all kept on a diet consisting of food produced from alfalfa only. The camelids produced less methane expressed on the basis of body mass (0.32±0.11 L kg⁻¹ d⁻¹) when compared to literature data on domestic ruminants fed on roughage diets (0.58±0.16 L kg⁻¹ d⁻¹). However, there was no significant difference between the two suborders when methane emission was expressed on the basis of digestible neutral detergent fiber intake (92.7±33.9 L kg⁻¹ in camelids vs. 86.2±12.1 L kg⁻¹ in ruminants). This implies that the pathways of methanogenesis forming part of the microbial digestion of fiber in the foregut are similar between the groups, and that the lower methane emission of camelids can be explained by their generally lower relative food intake. Our results suggest that the methane emission of Australia's feral camels corresponds only to 1 to 2% of the methane amount produced by the countries' domestic ruminants and that calculations of greenhouse gas budgets of countries with large camelid populations based on equations developed for ruminants are generally overestimating the actual levels.
Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty Zurich, University of Zurich, Zurich, Switzerland; ETH Zurich, Institute for Agricultural Sciences, Zurich, Switzerland.
Marie T
MT
Dittmann
Kamelhof Olmerswil, Neukirch/Thur, Switzerland.
Ullrich
U
Runge
Cochranton Veterinary Hospital, Cochranton, Pennsylvania, United States of America.
Richard A
RA
Lang
Zoological Institute, University of Basel, Basel, Switzerland.
Dario
D
Moser
Zurich Zoo, Zurich, Switzerland.
Cordula
C
Galeffi
ETH Zurich, Institute for Agricultural Sciences, Zurich, Switzerland.
Michael
M
Kreuzer
Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty Zurich, University of Zurich, Zurich, Switzerland.
Marcus
M
Clauss
D000818:Animals; D049628:Body Size; D001835:Body Weight; D002161:Camelids, New World / Q000378:metabolism*; D004032:Diet; D004063:Digestion; D005502:Food; D008697:Methane / Q000378:metabolism*
D008697:Methane