Dung avoidance as a possible mechanism in competition between wild and domestic ungulates: two experiments with chamois Rupicapra rupicapra

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 (parasite-free) 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 ungulate

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 (0.3260.11 L kg21 d21) when compared to literature data on domestic ruminants fed on roughage diets (0.5860.16 L kg21 d21). However, there was no significant difference between the two suborders when methane emission was expressed on the basis of digestible neutral detergent fiber intake (92.7633.9 L kg21 in camelids vs. 86.2612.1 L kg21 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

Seasonal body mass changes and feed intake in spectacled bears (Tremarctos ornatus) at Zurich Zoological Garden

Many animals display seasonal patterns of behaviour and metabolism that can be also be observed in captivity. During an obesity-control program in Andean bears (Tremarctos ornatus) at Zoo Zurich, a seasonal fluctuation of body mass war observed once ideal body mass had been reached. The focus of this study was the question if metabolism of a male and three female animals was affected by seasonality according to their seasonal breeding behaviour, using data on pelleted food intake (from computer controlled feeders) and body mass (from regular weighing). The pelleted diet in the feeder boxes was provided additionally to a daily ration containing vegetables, fruits, pellets for environmental enrichment, and fish. This daily ration was adjusted, within prescribed limits, by the animal keepers depending on the previous day's consumption. Formulas developed for dogs were used to estimate the metabolizable energy (ME) content of the diet and maintenance requirement of the bears depending on their individual body mass. Energy requirements for minimum walked distances between the feeders was calculated as well as energy requirement for fat accretion or energy gained from body fat by body mass loss. Body mass showed a seasonal fluctuation with maxima in spring and minima in autumn, in contrast to the pattern typically observed in animals from the temperate zone; in the male, the body mass maximum occurred later than in the females. Feed intake from feeder boxes peaked in autumn, at the beginning of body mass gain in the females. These patterns cannot be explained as seasonal adaptations to climatic changes in the zoo environment, but match the natural breeding season of Andean bears in their natural habitat, suggesting genetically fixed photoperiodic clues. The data indicate that body mass fluctuation in a range considered ideal for the species was mostly based on the additional food whose amount was adjusted - within limits - by the keepers on a daily basis. Such adjustment, without incurring the risk of obesity in bears that are known as voracious eaters, is a good example of the skill required in animal husbandry

Characterising an artiodactyl family inhabiting arid habitats by its metabolism: Low metabolism and maintenance requirements in camelids

To test whether camelids, as an artiodactyl family, are characterised by comparatively low energy expenditure, we collated literature data from experiments where at least one camelid and one ruminant species received the same diet, and literature data on camelid metabolism and energy requirements. Additionally, we measured the maintenance and resting metabolism in five alpacas, six llamas and five Bactrian camels by chamber respirometry. Irrespective of whether dry matter intake was expressed as g kg−0.75 day−1, g kg−0.9 day−1, or g kg−1.0 day−1, camelids ingested significantly less food than domestic ruminants (data available for sheep and goats). Although metabolic rates and energy requirements reported for camelids vary over a large range, they are generally below the ‘average’ basal mammal metabolism, and below published energy requirements for ruminants. The mean metabolic rates measured in this study were 215 ± 68, 261 ± 33 and 248 ± 51 kJ kg−0.75 day−1 for alpacas, llamas and Bactrian camels, respectively. The corresponding resting metabolic rates averaged at 144 ± 64, 164 ± 38 and 192 ± 48 kJ kg−0.75 day−1. These findings confirm that camelids in general are characterised by relatively low metabolism and food intake, which might explain why this previously diverse group is currently limited to arid environments with low food resources where a reduced metabolism represents an advantage

From left to right all through the night: Characteristics of lying rest in zoo elephants

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

Digesta retention patterns of solute and different-sized particles in camelids compared with ruminants and other foregut fermenters

The mean retention times (MRT) of solute or particles in the gastrointestinal tract 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 20mm) 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 1cm 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

Methane emission in L d⁻¹ of domestic ruminants (literature data) and camelids (own measurements, literature data included in the regression analysis and literature data not included due to differences in methodology) in relation to body mass.

<p>95% confidence intervals of the regression lines are given in brackets. R² values of the regression lines are 0.93 for ruminants and 0.91 for camelids. For data sources see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0094363#pone.0094363.s001" target="_blank">Table S1</a>.</p

Data on average CH₄ production of camelids and ruminants obtained by respiration measurements sorted by animal size.

<p>Note that sample size corresponds to the number of individuals used for measurements in the present study but to means from different publications for ruminants. Data sources are <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0094363#pone-0094363-t002" target="_blank">Table 2</a> for the present study and in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0094363#pone.0094363.s001" target="_blank">Table S1</a> for literature data. BM body mass, DMI dry matter intake, DEI digestible energy intake, dNDFI digestible neutral detergent fiber intake.</p

Methane emission in L per kg digestible neutral detergent fiber intake (dNDFI) of domestic ruminants (literature data) and camelids (own measurements, literature data included in the regression analysis and literature data not included due to differences in methodology) in relation to body mass.

<p>95% confidence intervals of the regression lines are given in brackets. R² values of the regression lines are 0.02 for ruminants and<0.001 for camelids. For data sources see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0094363#pone.0094363.s001" target="_blank">Table S1</a>.</p

Nutrient composition of the diet items used in the present study (in g/kg dry matter and MJ/kg dry matter for GE).

<p>TA total ash, CP crude protein, EE ether extracts, CF crude fiber, NDF neutral detergent fiber, ADF acid detergent fiber, ADL acid detergent lignin, GE gross energy.</p><p>*No. 2805, Provimi Kliba SA, Kaiseraugst, Switzerland.</p