Physical characteristics of rumen contents in two small ruminants of different feeding type,the mouflon (Ovis ammon musimon) and the roe deer (Capreolus capreolus)

In domestic ruminants, the stratification of forestomach contents – the results of flotation and sedimentation processes – is an important prerequisite for the selective particle retention in this organ. A series of anatomical and physiological measurements suggests that the degree of this stratification varies between browsing and grazing wild ruminants. We investigated the forestomach contents of free-ranging mouflon and roe deer shot during regular hunting procedures. There was no difference between the species in the degree by which forestomach ingesta separated according to size due to buoyancy characteristics in vitro. However, forestomach fluid of roe deer was more viscous than that of mouflon, and no difference in moisture content was evident between the dorsal and the ventral rumen in roe deer, in contrast to mouflon. Hence, the forestomach milieu in roe deer appears less favourable for gas or particle separation due to buoyancy characteristics. These findings are in accord with notable differences in forestomach papillation between the two species. In roe deer, particle separation is most likely restricted to the reticulum, whereas in mouflon, the whole rumen may pre-sort particles to a higher degree. The results suggest that differences in forestomach physiology may occur across ruminant species.     

Metabolic evidence of a 'rumen bypass' or a 'ruminal escape' of nutrients in roe deer (Capreolus capreolus)

As short chain fatty acids produced in the forestomach are insufficient to satisfy the energy requirements of the concentrate selecting roe deer (Capreolus capreolus), it is proposed that these animals may have other mechanisms to avoid energy losses due to microbial fermentation. Nutrients bypassing down the ventricular groove (rumen bypass) or ruminal escape of unfermented or partially fermented nutrients may be two alternatives. As metabolic evidence for incomplete fermentation in the forestomach we investigated: (1) the abundance of the sodium-dependent glucose co-transporter (SGLT1) in the duodenum; (2) enzyme activities of maltase, saccharase and alpha-amylase in duodenal and pancreatic tissue; and (3) the proportion of essential, polyunsaturated fatty acids in depot fat samples from ruminants of different feeding type and--for comparison--from animals with a simple stomach. The high abundance of SGLT1, high enzyme activity and the high proportion of polyunsaturated fatty acids in the concentrate selecting ruminants support the hypothesis of rumen bypass or ruminal escape of nutrients in roe deer and reflect differences in nutrient utilization by ruminants that belong to different feeding types.     

A typical browser, the roe deer, may consume substantial quantities of grasses in open landscapes

In open landscapes, grass leaves provide an abundant resource for ruminants, with potentially high nutritional value. However, their extensive digestion requires a long fermentation time, achieved through large rumen and the stratification of the rumen content. Due to anatomical and physiological differences, ruminants differ in their ability to process grass leaves. Particularly, the small roe deer, with its viscous saliva and unstratified rumen content, is generally classified as a strict browser. We hypothesised that roe deer may be able to use grass leaves in some circumstances, notably when the availability of other resources declines and when the quality of grass leaves is high. We expected that (1) grass leave consumption should be higher in open landscapes than in forest habitat because grasses are more widely available and more nutritious in open landscapes and (2) grass leave consumption should increase in winter when the availability of other resources declines. We assessed grass consumption by microscopic analysis of roe deer faecal pellets collected monthly both in forest habitat and in the surrounding open landscape. We found that both the occurrence and the proportion of grass leaves in the faeces were higher in the open landscape (predicted mean proportion 0.31) than in the forest (predicted mean proportion 0.05). In addition, the proportion of grass leaves in the faeces was higher in winter and lower in spring in both forest and open landscape. We suggest that roe deer are able to use grass leaves with unusually high nutritional quality in winter in this mild climate area. This involves a certain level of digestive plasticity to efficiently digest high quality grasses and may confer nutritional benefit to individuals feeding in an open landscape.     

Seasonal dynamics of digestion in relation to diet quality and intake in European roe deer (Capreolus capreolus)

Three tame, hand-reared adult roe deer (Capreolus capreolus) were fed a low-quality diet (blueberry stems) or high-quality concentrate either restricted or ad libitum in summer and winter. Total mean retention time (TMRT) and rumen retention time (RRT) were significantly longer, indigestible fill was significantly higher and apparent digestibility and intake were significantly lower when fed blueberry stems compared to concentrate. The feeding regimes of concentrate did not affect the digesta kinetic estimates, except that total fill and apprent digestibility were significantly higher when deer were fed ad libitum than when they were fed a restricted ration. TMRT was significantly longer when they were fed a restricted ration of blueberry stems than for ad libitum intake, whereas all other estimates were equal. Intake was significantly higher and TMRT and RRT were significantly shorter in summer compared to winter when they were fed concentrate. These findings support the theory that roe deer, as small-bodied concentrate selectors, are adapted to high intake, rapid turnover, and rapid digestion when fed high-quality concentrate. When fed a low-quality diet the roe deer may be limited by rumen bulk. A strategy based on increased rumen retention accompanied by increased cell-wall digestion has therefore severe limitations in roe deer. This indicates that roe deer are dependent on a selective feeding strategy to enhance winter survival.     

Autumn-winter diet overlap of fallow, red, and roe deer in forest ecosystems, Southern Poland

The wild population of fallow deer in Central Europe has grown considerably over the last decade. However, information on feeding habits of this alien species in relation to the indigenous red deer or roe deer, in areas of their co-occurrence, is scarce. A prevailing view maintains that their food-niches are distinct, although direct comparative studies have not been carried out. Therefore, the aim of the research was to compare the diets of fallow, red, and roe deer feeding in the same habitat. Research was based on the rumen contents of 242 animals hunted in the autumn-winter season in the forests of Southern Poland. The analyses demonstrated that fallow deer are moderate grazers in such conditions and eat more graminoids in comparison to red or roe deer (36.4% vs. 16.1% or 5.5%, respectively). On the other hand, it feeds on less browse (17.2% vs. 41.4%) or dwarf shrubs (8.4% vs. 19.0%) than red deer, and on less bramble (10.9% vs. 34.6%) or forbs (4.0% vs. 7.6%) in comparison to roe deer (P=0.05). Although the diets of the three deer species differ in terms of the proportion of each food type in their diet, overlapping of their food-niches is high (52.6%).     

Comparing life expectancy of three deer species between captive and wild populations

Life in zoological gardens provides a number of benefits to captive animals, resulting in an artificial reduction of the “struggle for life” compared to their free-ranging counterparts. These advantages should result in a higher chance of surviving from 1 year to the next, and thus in longer average life expectancies for captive animals, given that the biological requirements of the species are adequately met. Here, we compare the life expectancy of captive and free-ranging populations of three deer species (reindeer Rangifer tarandus, red deer Cervus elaphus, and roe deer Capreolus capreolus). Whereas captive reindeer and red deer had life expectancies equal to or longer than free-ranging individuals, the life expectancy of captive roe deer was shorter than that of free-ranging animals. These results support the impression that roe deer are difficult to keep in zoos, whereas reindeer and red deer perform well under human care. We suggest that the mean life expectancy of captive populations relative to that of corresponding free-ranging populations is a reliable indicator to evaluate the husbandry success of a species in captivity.     

Seasonal differences between moose and roe deer in ability to digest browse

The digestive capacity of free-living moose Alces alces (L.) and roe deer Capreolus capreolus (L.) for four plant species was studied with in vitro technique. Moose were found to digest all species better than roe deer. Individual variations were also smaller for moose. In moose the level of digestibility was the same both summer and winter, while roe deer shot in winter digested winter samples of bilberry Vaccinium myrtillus L. and to some extent Scots pine Pinus silvestris L. better than did summer roe deer. This was taken as evidence for a seasonal adaptation in the roe deer rumen. Digestibility of the plant material studied showed a strong negative correlation to the fiber content. The results are discussed in relation to winter problems for roe deer and possible food competition between moose and roe deer.     

In vitro digestibility of seasonal forages used by wapiti and roe deer in northeastern China

Seasonal changes in in vitro dry matter digestibility (IVDMD) of five forage classes (browses, sedges, forbs. ferns and the bark of Ulmus spp.) used by wapiti and roe deer were determined in relation to chemical composition, using the two-stage technique of in vitro trial with rumen inocula from one wapiti and one roe deer captured in winter. Wapiti and roe deer showed remarkable fluctuation in IVDMD among seasons and forage classes. IVDMD decreased from 43.8-64.3% in spring to 29.4-40.5% in winter for wapiti, and from 52.4-77.4% in spring to 25.9-36.5% in winter for roe deer. There was significant variation in IVDMD among species of browses for wapiti and roe deer. IVDMD ranged from 28.5% to 58.7% in twigs and from 39.8% to 58.2% in leaves for wapiti, and from 24.1% to 67.7% in twigs and from 40.0% to 71.7% in leaves for roe deer. Roe deer had higher IVDMD (40.0-71.7%) in both leaves and twigs of browses than wapiti (35.9-58.7%) during snow-free seasons, but IVDMD of twigs was lower for roc deer (25.9-36.5%) than wapiti (29.4-38.4%) in winter. Significant multiple correlation was found between NDF and ADF, and IVDMD in sedges, forbs and ferns for both wapiti and roe deer, whereas only roe deer showed the significant multiple correlation for leaves of browses.     

The consequences for deer of ingesting oilseed rape (Brassica napus): feeding experiments with roe deer (Capreolus capreolus) and red deer (Cervus elaphus)

In two experiments, in the growing season March–May, freshly harvested double-low oilseed rape ( Brassica napus ) plants were fed ad libitum to penned roe deer ( Capreolus capreolus ) and red deer ( Cervus elaphus ). In Experiment 1, oilseed rape was fed to five roe and 12 red deer as 60% of their daily dry matter (DM) intake for four weeks, after a two-week dietary change-over period. The rest of the diet comprised cattle-rearing pellets (33%) and freshly cut heather ( Calluna vulgaris ) plants (7%). In Experiment 2, oilseed rape was fed to seven roe and eight red deer as 100% of the diet for up to six weeks, after a two-week change-over period.
In both experiments, Heinz bodies were found in roe deer blood 2–3 weeks after the start of the change-over period, with a fall in mean packed cell volume (PCV) and blood glutathione (GSH) concentration. In Experiment 2, after 5–8 days of feeding on 100% oilseed rape, four roe deer showed signs of inappetance and were changed to a diet of 80% oilseed rape. At the same time, the other three roe deer had very low PCV (< 60% of normal values) and oilseed rape feeding was discontinued for those animals. The red deer showed no symptoms of haemolytic damage nor any change in blood GSH concentration in either experiment, but showed a gradual fall in PCV in Experiment 2. No other ill-effects were observed in any of the animals.
Intakes of oilseed rape (gDM/kg^0–75/day) were lower for the roe deer than the red deer in both experiments. The severity of haemolytic anaemia in the roe deer was related to the proportion of oilseed rape in the diet, rather than the amount ingested. It was concluded that the health of roe deer ingesting oilseed rape may be affected if other foods are not available.     

Rumen Ciliate Protozoa in Ohio White-tailed Deer (Odocoileus virginianus)

ABSTRACT. Rumen contents were obtained from 23 white-tailed deer (Odocoileus virginianus), located in the eastern portion of central Ohio. Samples were taken during late fall and winter over a 4-yr period, 1986–1990. Protozoan numbers ranged from 0.002 to 7.25 × 10⁶ per ml of rumen contents, with a mean of 2.96 × 10⁶. Six deer had protozoan concentrations higher than any values previously reported in ruminants. In all 23 animals, Entodinium dubardi was the only ciliate protozoan species present.     

Experimental evidence for density-dependence of home-range size in roe deer (<Emphasis Type="Italic">Capreolus capreolus</Emphasis> L.): a comparison of two long-term studies

The effect of experimental manipulation of population density on home-range size was investigated in two free-ranging roe deer (Capreolus capreolus) populations under contrasting environmental conditions. In these two long-term monitoring studies, one in Bogesund, Sweden (12 years) and one in Dourdan, France (10 years), deer density varied fourfold through varying culling pressure. Home-range data were collected by radio-tracking across the periods of contrasting density of the studies. We predicted that home-range size for females should vary in relation to the level of feeding competition, while for males, competition for mating opportunities should also influence range size, at least in summer when roe bucks are territorial. We found a highly consistent pattern over the two populations, with strong effects of deer density on home-range size, as well as significant differences between winter and summer ranges and between the sexes. Home ranges were consistently smaller at high density compared to low density. Males had larger ranges than females and this was particularly so during summer. Lastly, winter ranges were generally larger than summer ranges, particularly among females, although males at Dourdan had larger summer ranges compared to winter ranges. We suggest that the reduction of range size at high deer density during winter, as well as summer, is linked to the solitary behaviour and territorial social system of roe deer, with possible effects of dominance rank, even outside the mating season.     

Effects of density, climate, and supplementary forage on body mass and pregnancy rates of female red deer in Spain

The influence of short- and long-term (cohort) effects of climate and density on the life-histories of ungulates in temperate regions may vary with latitude, habitat, and management practices, but the life-histories of ungulates in the Mediterranean region are less well known. This study examined the short- and long-term effects of rainfall and absolute density on hinds in two of the southernmost populations of red deer (Cervus elaphus hispanicus) in Europe. One population received supplementary forage. Unlike more northerly latitudes, where red deer hinds lose body mass in winter as a result of adverse weather, in the Spanish populations, hinds did not lose body mass. Hinds in the population that received supplementary forage were heavier and more likely to become pregnant than were the hinds in the unsupplemented population. The likelihood of pregnancy occurring was strongly influenced by hind body mass; the proportion of yearlings that became pregnant was consequently lower in the unsupplemented population than in the population that received supplementary forage. Cohort effects on hind body mass (negative for density and positive for rainfall at birth) and on the probability of pregnancy (negative for density at birth) were apparent only in the unsupplemented population, which implies that supplemental feeding may partially compensate for negative density-dependent factors during early growth, and that supplemented deer hinds may experience reduced selection pressures. These results reflect the particular seasonal variation in the abundance and quality of food in Mediterranean habitats. The delayed effects of climate and density at birth on adult hind body mass and the prevalence of pregnancy probably affects population dynamics and constitutes a mechanism by which cohort effects affect the population dynamics in Iberian red deer. The management of Iberian red deer populations should take into account cohort effects and supplemental feeding practices, which can buffer density- and climate-dependent effects and reduce natural selection pressures.     

Selenium concentration in liver and kidney of free living animals (roe and red deer) from West Pomerania (Poland)

The aim of this study was to determine concentrations of selenium in the liver and kidneys of roe deer and red deer from West Pomerania, depending on the season. Altogether, samples from 169 animals were collected (96 from roe deer and 73 from red deer) in 2003–2007. The mean concentration of selenium in the liver of red deer and roe deer was 0.37 μg/g and 0.62 μg/g dry weight, respectively. In kidneys, Se concentration was 2.72 μg/g d.w. in red deer and 2.99 μg/g d.w. in roe deer. In roe deer, liver selenium concentration in autumn was significantly higher than in winter (P < 0.05) and spring (P < 0.01) and significantly lower in spring than in summer (P < 0.05); likewise, kidney selenium concentration was higher in autumn than in summer. In deer, no statistically significant season-related differences were observed for liver selenium concentrations. In red deer kidneys, selenium concentration was the lowest in summer, significantly lower than in autumn and winter. Low selenium concentrations in the analyzed tissues show that the animals live in areas deficient in this element.     

Activity of cellulolytic enzymes in the contents of reticulorumen and caecocolon of roe deer (Capreolus capreolus)

Selective ruminants, which prefer easily digestible plants, cannot digest fibrous forage as well as grass eaters. Low enzyme activity or short retention time of ingesta particles in fermentation chambers appeared to be responsible for reduced cellulose breakdown. Seasonal activity of cellulolytic enzymes, cellulose concentration and protozoa population in reticulorumen (RR) and caecocolon (CC) of roe deer as a typical concentrate selector were investigated. Cellulase activities were lowest in winter when cellulose concentration in RR contents were highest. Highest enzyme activities and lowest cellulose concentration were measured in early spring. Cellulolytic activities were significantly correlated with the number of protozoa in RR. Only one entodinomorphic genus was identified in the RR. The enzyme activities in CC were far lower compared with those in RR. Low cellulose digestion in the RR cannot be compensated for by cellulose breakdown in the CC. The reduced cellulose digestion of roe deer may be attributed to the short retention time of food particles in spring and summer, whereas decreased colonisation of microorganisms in the rumen may be the main reason for low cellulose breakdown in winter.     

Density of Wild Prey Modulates Lynx Kill Rates on Free-Ranging Domestic Sheep

Understanding the factors shaping the dynamics of carnivore–livestock conflicts is vital to facilitate large carnivore conservation in multi-use landscapes. We investigated how the density of their main wild prey, roe deer Capreolus capreolus, modulates individual Eurasian lynx Lynx lynx kill rates on free-ranging domestic sheep Ovis aries across a range of sheep and roe deer densities. Lynx kill rates on free-ranging domestic sheep were collected in south-eastern Norway from 1995 to 2011 along a gradient of different livestock and wild prey densities using VHF and GPS telemetry. We used zero-inflated negative binomial (ZINB) models including lynx sex, sheep density and an index of roe deer density as explanatory variables to model observed kill rates on sheep, and ranked the models based on their AICc values. The model including the effects of lynx sex and sheep density in the zero-inflation model and the effect of lynx sex and roe deer density in the negative binomial part received most support. Irrespective of sheep density and sex, we found the lowest sheep kill rates in areas with high densities of roe deer. As roe deer density decreased, males killed sheep at higher rates, and this pattern held for both high and low sheep densities. Similarly, females killed sheep at higher rates in areas with high densities of sheep and low densities of roe deer. However, when sheep densities were low females rarely killed sheep irrespective of roe deer density. Our quantification of depredation rates can be the first step towards establishing fairer compensation systems based on more accurate and area specific estimation of losses. This study demonstrates how we can use ecological theory to predict where losses of sheep will be greatest, and can be used to identify areas where mitigation measures are most likely to be needed.     

Comparative Analysis of Ultradian and Circadian Behavioural Rhythms for Diagnosis of Biorhythmic State of Animals

A chronobiological procedure has been developed for evaluation of living conditions, behaviour and internal state of free-ranging animals. It is based on continuous recordings of activity and feeding with subsequent comparison of levels, daily patterns as well as daily and ultradian rhythms. Telemetric observations were carried out on alpaca, sheep, Przewalski horse, roe deer, red deer and mouflon under various conditions. The time patterns of the different species were analysed macroscopically and by autocorrelation function and power spectral analysis. A stable ultradian structure of behaviour was obvious especially for ruminants. A more unstable, adaptive time pattern was found in Przewalski horses. Activity as a multi-purpose behaviour was generally more variable than feeding which in most cases was of clearly rhythmic and harmonic structure. Degrees of Functional Couplings (DFCs) were used for comparison of rhythmic structure. DFCs express the percentage of the circadian component and harmonic ultradian components in relation to all rhythmic components of a spectrum. They were found to be high in well adapted, healthy and undisturbed individuals but were lowered during periods of adaptation, sickness or social interactions.     

How does oak mast seeding affect the feeding behavior of sympatric red and roe deer?

Oak reproduction is characterized by mast seeding with high inter-annual fluctuations in fruit production. Such resource pulses can greatly affect ecosystem functioning and may cause seed consumers to alter their mobility, demography, or diet. Consequences of mast seeding for seed consumers remain poorly understood as their long timescale makes them difficult to study. We investigated impacts of oak mast seeding on the feeding behavior of two sympatric European deer species: red deer (Cervus elaphus) and roe deer (Capreolus capreolus). We analyzed their rumen content over a 31-year period in tandem with 10 years of data on oak fructification (i.e. 8 years of field monitoring and two modelled years). Acorn production is strongly correlated with consumption by both deer species. In years of high fructification, acorns represent more than 50% and 35% of red and roe deer diet, respectively, confirming assumptions that deer favor acorns when these are available. Red deer eat more acorns than roe deer both between and within years. High acorn production in mast years appears to saturate the capacity of deer to consume acorns. As the proportion of acorns increase in their diet, red deer eat more grasses and less conifer browse. No dietary shift was found for roe deer. By inducing dietary shifts in consumers, oak mast seeding can have cascading effects on ecosystem processes, notably on the damages on conifers caused by red deer and the consequences for forest dynamics.     

Does Supplemental Feed Increase Selective Foraging in a Browsing Ungulate?

ABSTRACT Provision of supplemental feed to large herbivores is a common management practice that may motivate selective foraging, thereby influencing plant community composition. Our objective was to assess the effect of a high-quality supplement on diet composition and nutritional quality for white-tailed deer (Odocoileus virginianus). We permanently released hand-reared deer into 4 81-ha enclosures; in 2 enclosures we provided a pelleted supplement. We conducted bite-count studies seasonally to assess diet composition and quality. Supplemented deer reduced mast (fruits and pods of woody plants and cacti) in their diets (P < 0.019) during spring and autumn compared to unsupplemented deer. Diets of deer in supplemented enclosures had 2 times greater proportion of browse during spring (P = 0.065) and 5 times greater proportion of forbs during autumn (P = 0.007). Quality of the forage portion of the diet did not vary by treatment during winter or summer. Metabolizable energy concentration was 13% greater (P = 0.054) in spring and digestible protein content was 3 times greater (P = 0.006) during autumn in diets of supplemented compared to unsupplemented deer. Our results support the selective foraging hypothesis during autumn but not during winter, spring, or summer. Furthermore, white-tailed deer did not reduce the proportion of their diet composed of browse, but did reduce consumption of mast. Supplemented deer continued to eat poor-quality, chemically defended forage, perhaps to alleviate ruminal acidosis induced by the supplement or because nutrients in the supplement increased the deer's ability to detoxify chemically defended browses. A decline in mast consumption by supplemented deer could influence plant communities, depending on the role of deer in seed dispersal and seed predation. Impacts of supplemental feed on selective foraging of white-tailed deer in shrub-dominated rangelands are more complex than suggested by previous research. Long-term studies of vegetation communities are needed before wildlife managers will be able to fully incorporate effects of supplemental feed into management decisions.     

Bacteria and Methanogens Differ along the Gastrointestinal Tract of Chinese Roe Deer (Capreolus pygargus)

The current study provides the insight into the bacteria in the gastrointestinal tract (GIT) and methanogens presented in the rumen and cecum of the Chinese roe deer (Capreolus pygargus). The ruminal, ileal, cecal, and colonic contents, as well as feces, were obtained from each of the three, free-range, roe deer ingesting natural pasture after euthanasia. For the bacterial community, a total of 697,031 high-quality 16S rRNA gene sequences were generated using high-throughput sequencing, and assigned to 2,223 core operational taxonomic units (OTUs) (12 bacterial phyla and 87 genera). The phyla Firmicutes (51.2%) and Bacteroidetes (39.4%) were the dominant bacteria in the GIT of roe deer. However, the bacterial community in the rumen was significantly (P<0.01) different from the other sampled regions along the GIT. Secondly, Prevotella spp., Anaerovibrio spp., and unidentified bacteria within the families Veillonellaceae and Paraprevotellaceae were more abundant in the rumen than in the other regions. Unidentified bacteria within the family Enterobacteriaceae, Succinivibrio spp., and Desulfovibrio spp. were more predominant in the colon than in other regions. Unidentified bacteria within the family Ruminococcaceae, and Bacteroides spp. were more prevalent in the ileum, cecum and fecal pellets. For methanogens in the rumen and cecum, a total of 375,647 high quality 16S rRNA gene sequences were obtained and assigned to 113 core OTUs. Methanobrevibacter millerae was the dominant species accounting for 77.3±7.4 (S.E) % and 68.9±4.4 (S.E) % of total sequences in the rumen and cecum of roe deer, respectively. However, the abundance of Methanobrevibacter smithii was higher in the rumen than in the cecum (P = 0.004). These results revealed that there was intra variation in the bacterial community composition across the GIT of roe deer, and also showed that the methanogen community in the rumen differed from that in the cecum.