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.

The mean retention time (MRT) of solute or particles in the gastrointestinal tract (GIT) and the forestomach (FS) are crucial determinants of digestive physiology in herbivores. Besides ruminants, camelids are the only herbivores that have evolved rumination as an obligatory physiological process consisting of repeated mastication of large food particles, which requires a particle sorting mechanism in the FS. Differences between camelids and ruminants have hardly been investigated so far. In this study we measured MRTs of solute and differently-sized particles (2, 10, and 20 mm), and the ratio of large-to-small particle MRT, i.e., the selectivity factors (SF10/2mm, SF20/2mm, SF20/10mm), in three camelid species: alpacas (Vicugna pacos), llamas (Llama glama), and Bactrian camels (Camelus bactrianus). The camelid data were compared with literature data from ruminants and non-ruminant foregut fermenters (NRFF). Camelids and ruminants both had higher SF10/2mmFS than NRFF, suggesting convergence in the function of the FS sorting mechanism in contrast to NRFF, in which such a sorting mechanism is absent. The SF20/10mmFS did not differ between ruminants and camelids, indicating that there is a particle size threshold of about 1 cm in both suborders above which particle retention is not increased. Camelids did not differ from ruminants in MRT2mmFS, MRTsoluteFS and the ratio MRT2mmFS/MRTsoluteFS, but they were more similar to 'cattle-' than to 'moose-type' ruminants. Camelids had higher SF10/2mmFS and higher SF20/2mmFS than ruminants, indicating a potentially slower particle sorting in camelids than in ruminants, with larger particles being retained longer in relation to small particles. sorting mechanism in contrast to NRFF, in which such a sorting mechanism is absent. The SF 20/10mm FS did not differ between ruminants and camelids, indicating that there is a particle size threshold of about 1 cm in both suborders above which particle retention is not increased. Camelids did not differ from ruminants in MRT 2mm FS, MRT solute FS, and the ratio MRT 2mm FS/MRT solute FS, but they were more similar to 'cattle-' than to 'moose-type' ruminants. Camelids had higher SF 10/2mm FS and higher SF 20/2mm FS than ruminants, indicating a potentially slower particle sorting in camelids than in ruminants, with larger particles being retained longer in relation to small particles.

No abstract

Wild ungulates often adjust spatial behaviour where they coexist with livestock. In European mountains, chamois Rupicapra rupicapra or R. pyrenaica commonly avoid alpine pastures used by domestic sheep. Mechanisms leading to competitive losing out of the wild species are not well understood, but mostly, resource competition is inferred and sometimes demonstrated. We hypothesised that chamois need to minimise the risk of intestinal parasite uptake and therefore would avoid pastures contaminated with sheep dung. We tested this in two experiments by contaminating feeding patches of wild and captive chamois with (parasitefree) sheep faeces. Wild chamois did not avoid grazing sites or plots on which sheep dung had been placed at a (low) density representing the commonly encountered situation in the Swiss Alps. Captive chamois strongly reduced browsing time on small trees given for food when the surroundings of the trees were sprayed with a watery faecal solution. We concluded that the odour signalled a potential high risk of parasite infection to the captive chamois, whereas the density of sheep dung on the grazing site of wild chamois was not high enough to be perceived as a risk. The need to minimise endoparasite uptake from faeces may therefore play a role in driving spatial behaviour of wild ungulates and could result in competitive imbalance between wild and domestic ungulates.

Despite increased research during the past years, many characteristics of resting behavior in elephants are still unknown. For example, there is only limited data suggesting elephants express longer lying bouts and increased total nightly lying durations on soft substrates as compared to hard surfaces. Additionally, it has not been investigated how frequently elephants change body sides between lying bouts.Here we present these characteristics based on observations of nighttime lying behavior in 10 zoo elephants (5 African Loxodonta africana and 5 Asian Elephas maximus elephants) living in five different European facilities. We found that elephants housed on soft substrates have significantly increased total lying durations per night and longer average lying bouts. Furthermore, at 70%−85% of all bouts, a consistently higher frequency of side change between lying bouts occurred on soft substrates, leading to an overall equal laterality in resting behavior. Deviations from this pattern became evident in elephants living on nonsand flooring or/and in nondominant individuals of nonfamily groups, respectively. Based on our findings, we consider elephants to normally have several lying bouts per night with frequent side changes, given an appropriate substrate and healthy social environment. We encourage elephant-keeping facilities to monitor these characteristics in their elephants' nighttime behavior to determine opportunities for further improvements and detect alterations putatively indicating social or health problems in individual elephants at an early stage.