Deer Fawns Research Articles

Captive roe deer ( Capreolus capreolus) select for low amounts of tannic acid but not quebracho: fluctuation of preferences and potential benefits

Browsing ruminants have been shown to tolerate a certain amount of tannins in their natural diet, and preference trials with captive roe deer ( Capreolus capreolus) have suggested an active selection for a low dose of hydrolysable tannins. In this study, we investigated the preference patterns for tannic acid, a source of hydrolysable tannins, and quebracho, a source of condensed tannins, in a series of preference trials with captive roe deer over time, using a pelleted feed that differed only in the respective tannin content. Additionally, two groups of four hand-raised roe deer fawns were fed either a control or a 3% tannic-acid containing diet and physiological parameters were compared after 7.5 months. There were large differences in preference patterns between the individual roe deer groups; quebracho was mostly avoided, whereas tannic acid was actively included in the diet in differing, low proportions. However, one group consistently preferred the quebracho diet over both the control or the tannic acid diet. For the tannic acid, the preference pattern often revealed an initial period of high preference, followed by a stable period of a moderate preference. The fawns on the tannic acid diet had a lower pellet intake and a higher relative mass gain than the fawns on the control diet; differences in salivary tannin-binding capacity and in blood antioxidant status were below significance. These results are the first indications of potential benefits of a low-dose tannin diet, which need further confirmation. The results of the preference trials demonstrate that the time pattern of tannin intake is not constant, and pose the question about the validity of short-term preference trials in general.

Spatial variation in springtime food resources influences the winter body mass of roe deer fawns.

It is well established that the dynamics of mammalian populations vary in time, in relation to density and weather, and often in interaction with phenotypic differences (sex, age and social status). Habitat quality has recently been identified as another significant source of individual variability in vital rates of deer, including roe deer where spatial variations in fawn body mass were found to be only about a tenth of temporal variations. The approach used was to classify the habitat into blocks a priori, and to analyse variation in animal performance among the predefined areas. In a fine-grained approach, here we use data collected over 24 years on 1,235 roe deer fawns captured at known locations and the plant species composition sampled in 2001 at 578 sites in the Chizé forest to determine the spatial structure at a fine scale of both vegetation and winter body mass of fawns, and then to determine links between the two. Space and time played a nearly equal role in determining fawn body masses of both sexes, each accounting for about 20% of variance and without any interaction between them. The spatial distribution of fawn body mass was perennial over the 24 years considered and predicted values showed a 2 kg range according to location in the reserve, which is much greater than suggested in previous work and is enough to have strong effects on fawn survival. The spatial distribution and the range of predicted body masses were closely similar in males and females. The result of this study is therefore consistent with the view that the life history traits of roe deer are only weakly influenced by sexual selection. The occurrence of three plant species that are known to be important food items in spring/summer roe deer diets, hornbeam ( Carpinus betulus), bluebell ( Hyacinthoides sp.) and Star of Bethlehem ( Ornithogalum sp.) was positively related to winter fawn body mass. The occurrence of species known to be avoided in spring/summer roe deer diets [e.g. butcher's broom ( Ruscus aculeatus) and beech ( Fagus sylvatica)], was negatively related to fawn body mass. We conclude that the spatial variation in the body mass of fawns in winter in this forest is as important as the temporal variation, and that the distribution of plant species that are actively selected during spring and summer is an important determinant of spatial variation in winter fawn body mass. The availability of these plants is therefore likely to be a key factor in the dynamics of roe deer populations.

Group composition and cohesion in sympatric white-tailed deer and mule deer

White-tailed deer (Odocoileus virginianus) have been reported to live in smaller groups than mule deer (Odocoileus hemionus). Group size, however, generally varies with habitat conditions, and no comparison has been made between the social structures of the two species living in the same ecological conditions. I compared the size, composition, and stability of groups formed by sympatric whitetails and mule deer living in a prairie habitat in southern Alberta. Seasonal trends were similar for the two species. Females and fawns usually formed small groups during summer. Larger mixed-sex groups became increasingly common during winter, well after the breeding season. Despite the similar seasonal trend, mule deer were significantly more likely than whitetails to occur in relatively large groups composed of both sexes during winter, and whitetails were more likely to occur in small female groups. Mule deer groups were more stable than whitetail groups, and marked mule deer fawns developed strong associations with other known fawns. Habitat variation was limited and was not related to group size. These results show that the composition and cohesion of whitetail and mule deer groups differ, even when the species live in similar circumstances. The differences in grouping behaviour, larger more cohesive groups formed by mule deer than by whitetails, are consistent with those expected to result from the selection pressure of predation.

Cyclic voles, prey switching in red fox, and roe deer dynamics – a test of the alternative prey hypothesis

Medium‐sized predators sometimes switch to alternative prey species as their main prey declines. Our objective of this study was to test the alternative prey hypothesis for a medium sized predator (red fox, Vulpes vulpes), a small cyclically fluctuating main prey (microtine voles) and larger alternative prey (roe deer fawns, Capreolus capreolus). We used long‐term time series (28 years) on voles, red fox and roe deer from the Grimsö Wildlife Research Area (59°40′N, 15°25′E) in south‐central Sweden to investigate interspecific relationships in the annual fluctuations in numbers of the studied species. Annual variation in number of roe deer fawns in autumn was significantly and positively related to vole density and significantly and negatively related to the number of fox litters in the previous year. In years of high vole density, predation on roe deer fawns was small, but in years of low vole density predation was more severe. The time lag between number of fox litters and predation on fawns was due to the time lag in functional response of red fox in relation to voles. This study demonstrates for the first time that the alternative prey hypothesis is applicable to the system red fox, voles and roe deer fawns.

Cross-protection between epizootic hemorrhagic disease virus serotypes 1 and 2 in white-tailed deer.

Viruses in the epizootic hemorrhagic disease (EHD) serogroup are the most frequent cause of hemorrhagic disease in the southeastern United States, but nothing is known about cross-protection between the two EHD serotypes (EHDV-1 and EHDV-2) present in this region. We experimentally tested whether deer surviving EHDV-2 infection would be protected against subsequent infection with EHDV-1, and used field data to examine the possibility of reciprocal cross-protection. Eleven white-tailed deer fawns (Odocoileus virginianus) were experimentally infected with EHDV-2 and later challenged with EHDV-1. Two EHDV-2-naïve fawns also were infected with EHDV-1. Deer were monitored via physical examination, complete blood counts, clotting profiles, viral isolation, and serology, and each animal was assigned a quantitative clinical disease severity score based on presence of certain physical and clinical parameters. Infection of naïve controls with EHDV-1 caused severe clinical disease and death of both fawns, whereas deer previously infected with EHDV-2 exhibited no or minimal signs of disease. Thus, infection with EHDV-2 conferred protection against disease caused by subsequent EHDV-1 infection. Although prior EHDV-2 exposure protected deer from severe clinical disease, it did not prevent infection nor viremia indicating they could still act as virus amplifying hosts. These experimental infections suggest that EHDV-1 and 2 may exist in a state of mutual permissiveness.

Atlantoaxial Instability in a White-tailed Deer Fawn (Odocoileus virginianus)

On 14 March 2001, an 8 mo old, male white-tailed deer (Odocoileus virginianus) was found in lateral recumbency exhibiting neurologic signs including inability to rise, opisthotonus, paddling, and respiratory distress. There was evidence of minor cranial trauma. Postmortem examination revealed atlantoaxial instability with ventral deviation of the axis due to malformation of the caudal atlas and cranial axis. Given the age of the fawn, the instability was assumed to be congenital with minor trauma inducing severe, acute neurologic signs.

Roe deer Capreolus capreolus fawns and mowing ‐ mortality rates and countermeasures

Besides red fox Vulpes vulpes predation, mowing is probably the most important mortality factor for roe deer Capreolus capreolus neonates in areas of intensive agriculture. Using radio‐transmitters on roe deer neonates in south‐central Sweden, I estimated mortality caused by mowing and tested and evaluated a traditional method to decrease this kind of mortality. During 1997–1999 fawn mortality caused by mowing was estimated at 25–44% of the yearly recruitment. Fawns were at risk for at least up to one month of age. The method tested uses scaring devices made of plastic sacks that are set out before mowing. The idea is that this will prevent female roe deer from placing their fawns in the field and make them remove the ones already hiding there. Black plastic sacks were attached to approximately 2‐m long poles and placed in hay fields where marked fawns were bedded. During 1998–1999,14 separate experiments were performed. Out of 22 fawns bedded in the vicinity of sacks, 18 were removed the day after the sacks were set out and three were removed on the second day. The fawns were always removed to another field or habitat patch. Fawns in the experiments were removed to a higher degree than fawns used as a control, and they were moved longer distances than both control fawns and the distances moved during the days before the experiment. The results imply that the use of this method is effective in reducing the mortality of roe deer fawns.

Milk containing Mycobacterium bovis as a source of infection for white-tailed deer fawns ( Odocoileus virginianus)

Setting: White-tailed deer represent the first wildlife reservoir of Mycobacterium bovis in the United States. The behavior of does with nursing fawns provides several potential mechanisms for disease transmission. Little information exists concerning transmission between doe and fawn, specifically transmammary transmission. Objective: Determine if fawns can become infected by ingestion of milk replacer containing M. bovis, thus simulating transmission from doe to fawn through contaminated milk. Design: Seventeen, 21-day-old white-tailed deer fawns were inoculated orally with 2×10 8 CFU (high dose, n=5), 2.5×10 5 to 2.5×10 6 CFU (medium dose, n=5), and 1×10 4 CFU (low dose, n=5) of M. bovis in milk replacer. Dosages were divided equally and fed daily over a 5-day period. Positive control fawns ( n=2) received 1×10 5 CFU of M. bovis instilled in the tonsillar crypts. Fawns were euthanized and examined 35–115 days after inoculation and various tissues collected for bacteriologic and microscopic analysis. Results: All fawns in the tonsillar, high oral and medium oral dose groups developed generalized tuberculosis involving numerous organs and tissues by 35–84 days after inoculation. Three of five fawns in the low-dose oral group had tuberculous lesions in the mandibular lymph node, and one of five had lesions in the medial retropharyngeal lymph node when examined 115 days after inoculation. Conclusion: White-tailed deer fawns can become infected through oral exposure to M. bovis. Therefore, the potential exists for fawns to acquire M. bovis while nursing tuberculous does.

Contributions of forage competition, harvest, and climate fluctuation to changes in population growth of northern white-tailed deer.

Recently there has been considerable interest in determining the relative roles of endogenous (density-dependent) and exogenous (density-independent) factors in driving the population dynamics of free-ranging ungulates. We used time-series analysis to estimate the relative contributions of density-dependent forage competition, climatic fluctuation, and harvesting on the population dynamics of white-tailed deer (Odocoileus virginianus) in Nova Scotia, Canada, from 1983 to 2000. A model incorporating the population density 2years previous, an interaction term for the harvest of females and population density 2years previous, and the total snowfall during the previous 2 winters explained 80% of the variation in inter-annual population growth rate. Natality of adult females was negatively related to deer density during the present winter, whereas that of yearlings may have been correlated with the snowfall of three winters previous. Natality of fawns was related to deer density and total snowfall during the previous winter. Coyotes (Canis latrans) prey extensively on deer fawns in northeastern North America and the annual harvest of snowshoe hares (Lepus americanus), the major alternate prey of coyotes, explained 48% of the inter-annual variation in fawn recruitment. The proportions of fawn, yearling, and adult deer suffering from severe malnutrition during late winter were all correlated with deer density during the present winter. We conclude that the limiting effects of winter weather on over-winter survival of deer may be cumulative over two consecutive winters. During the late 1980s, density dependence and winter severity acted in concert to effect substantial declines in deer population growth both by effecting winter losses directly and by exacerbating predation by coyotes. During this period liberal harvesting did not relieve density-dependent forage competition and probably accelerated the decline.

Daily incremental lines in sika deer (Cervus nippon) dentine.

This work was designed to observe the dentine incremental lines of the sika deer (Cervus nippon) fawns and to investigate their periodicity using the chronological labeling method with fluorochromes. The incremental lines were observed in decalcified specimens stained by Bodian's silver technique, and the fluorescence-labeled lines were observed in undecalcified and ground specimens. In the silver stained specimens, there were two types of lines, deeply stained thick lines and faintly stained minute regular incremental lines. The intervals and staining intensities of the deeply stained thick lines were very similar to those of the fluorescence-labeled lines in the ground specimens obtained from the same tooth, and hence, it appeared that the both lines were identical. The number of minute incremental lines between the deeply stained thick lines was the same as that of days between the time when each fluorescent labeling injection was made. Therefore, it seemed that each minute incremental line was formed each day. The possibility of age estimation in days using diurnal dentine increments was discussed.

Influences of winter supplemental feeding on the energy balance of white-tailed deer fawns in New Hampshire, U.S.A.

The purpose of this study was to determine the influence of supplemental feeding on the energy balance of white-tailed deer (Odocoileus virginianus) in northern New Hampshire, U.S.A., during January–March 1997. We measured the field metabolic rate (FMR) and energy balance of 10 (5 males and 5 females) supplementally fed wild fawns with doubly labeled water over 19–21 days. We tested whether percent acid detergent fiber (ADF) and percent neutral detergent fiber in deer fecal samples predicted the proportion of supplemental feed (pelleted concentrate) in the diet of deer. The mean FMR of fawns was 758.4 kJ·kg–0.75·d–1 (range = 535.9–1032.8 kJ·kg–0.75·d–1), or 2 × their basal metabolic rate (BMR). The mean FMR of male fawns was >30% higher than that of female fawns. Percent body fat (12.1 ± 1.4% (mean ± SE)) and mass loss (3.0 ± 0.9%) varied among fawns, suggesting that an individual high FMR was not detrimental to energy balance and was related to availability of feed. We estimated that a high FMR (>2 × BMR) could be maintained only if fawns consumed about 1 kg of supplemental feed daily. Radiotelemetry data indicated that the number and juxtaposition of feeding sites in an area probably influenced home range and activity of deer. Percent ADF in feces provided the best prediction of percent grain in the diet (% grain = –0.048(% ADF)2 + 1.523(% ADF) + 96.467; r2 = 0.69) and was useful for identifying populations consuming supplemental pelleted concentrate. Biologists should expect that the influence of winter feeding on energy balance and survival will vary according to the interrelationships of deer density, food availability, and winter severity at feeding sites.

Oral and fecal shedding of epizootic hemorrhagic disease virus, serotype 1 from experimentally infected white-tailed deer.

Epizootic hemorrhagic disease (EHD), one of the most important infectious diseases of white-tailed deer (Odocoileus virginianus), is vectored by species of midges in the genus Culicoides. Although vector borne, fecal shedding of EHD virus, serotype 2 has been reported from infected deer in a previous study. To evaluate the potential for fecal and oral shedding, oral and rectal swabs were obtained on day 8 post-inoculation from white-tailed deer fawns experimentally infected with EHD virus, serotype 1 (EHDV-1). Eight deer were viremic for EHDV-1; virus was detected in oral swabs from three (38%) and in rectal swabs from four (50%). The ability to isolate EHDV-1 in oral secretions or feces was not dependent on being able to detect clinical disease. These results indicate that in a relatively large proportion of EHDV-1 infected deer, virus can be detected in feces and oral secretions. Although more work is necessary, such shedding may be important in experimental studies or pen situations where deer-to-deer contact is prevalent and intense.

Population Characteristics of Sympatric Mule and White-Tailed Deer on Rocky Mountain Arsenal, Colorado

We studied population characteristics of sympatric mule deer (Odocoileus hemionus) and white-tailed deer (O. virginianus) on Rocky Mountain Arsenal, Colorado, USA, 1990-1993. Both species' populations increased during the study. Mule deer increased nearly 3 times faster than white-tailed deer. We did not detect any differences in adult survival, overwinter fawn survival, or natality between these species. Differences in population growth rates over 4 years were attributed to an initial 4:1 numerical advantage for mule deer and a 2:1 advantage in early survival of mule deer fawns.

Experimental adenovirus hemorrhagic disease in white-tailed deer fawns.

Infection with a newly described endotheliotropic adenovirus was the cause of a 1993 epizootic reminiscent of hemorrhagic disease in California mule deer (Odocoileus hemionus columbianus and O. hemionus hemionus). Pulmonary edema and intestinal luminal hemorrhage, or necrotizing stomatitis associated with systemic or localized vasculitis, respectively, were common lesions seen in animals that died during the epizootic. In order to determine if white-tailed deer (Odocoileus virginianus) also are susceptible to infection and fatal disease with the deer adenovirus, eight white-tailed deer fawns (4- to 6-mo-old) were inoculated with purified deer adenovirus. Four were inoculated intravenously and four were inoculated through the mucous membranes. Seven days post-inoculation, one of the fawns inoculated intravenously died. Pulmonary edema and hemorrhagic enteropathy were associated with pulmonary and intestinal vasculitis with systemic multiorgan distribution of endotheliotropic adenovirus as demonstrated by transmission electron microscopy and immunohistochemistry. Adenovirus was reisolated from lung homogenates of the fawn that died of adenovirus hemorrhagic disease.

Depredacion en crías de venado cola blanca (Odocoileus virginianus texanus) por coyote (Canis latrans) en una Unidad de Manejo y aprovechamiento del Norte de Nuevo León, México

Deer fawn predation was evaluated through the analysis of 1,117 coyote scats, which were collected in one-year period, from August 1997 to August 1998 at the UMA San Jose, Anahuac, Nuevo Leon, Mexico. Fawn mortality did not produce considerable impact on deer population. Moreover, in open areas, other wildlife management alternatives produce better results than the coyote control techniques.

Higher mortality of smaller sika deer fawns

Bodyweight, breast girth and hind‐foot length were compared in sika deer fawns (Cervus nippon Temminck) that were shot or had died naturally. The study site was Mount Goyo, in northern Japan. Samples were collected in January and February every year from 1982 to 1991 for the dead fawns and from 1990 to 1992 for the living fawns. The average bodyweight and the variation in bodyweight was significantly smaller in the dead fawns than in the living ones, suggesting a higher mortality rate in smaller fawns. The mean breast girth and hind‐foot length were also significantly smaller in the dead fawns. Two possibilities are suggested: (i) the smaller fawns were born later than the larger fawns and grew at normal rates; or (ii) the smaller and larger fawns were born in a similar period but grew at different rates thereafter.

Association of Moraxella ovis with keratoconjunctivitis in mule deer and moose in Wyoming.

Six cases of infectious keratoconjunctivitis (IKC) in mule deer (Odocoileus hemionus) and moose (Alces alces) in Wyoming (USA) were investigated during fall and winter of 1995 and 1996. Excessive lacrimation, mucopurulent conjunctivitis, keratitis, and corneal opacity were observed in mule deer. Moose had severe mucopurulent conjunctivitis, keratitis, and corneal ulceration. Hemolytic, non-piliated Moraxella ovis was isolated from two mule deer and two moose. We attempted to reproduce IKC in three mule deer fawns using an isolate of M. ovis from a clinically affected mule deer. These fawns did not develop clinical signs of infection and the bacterium was not reisolated from inoculated deer. Inoculated deer may not have developed clinical signs because deer were not exposed to ultraviolet light or mechanical insult before inoculation. In addition, the isolate used for inoculation may have lost virulence factors through passage, or M. ovis may not have been the primary pathogen responsible for clinical disease in the natural cases of IKC we investigated. The etiology of IKC in free-ranging wild ruminants remains poorly understood.

Spermatozoan numbers and testicular characteristics of male white-tailed deer fawns during the mating season

Testicular spermatozoan numbers, testes weight, testes leght, body weight, and kidney fat index (KFI) were obtained for male white-tailed deer Odocoileus virginianus (Zimmerman, 1780) fawns during the mating season at the Savannah River Site (SRS) in South Carolina.

Growth of European roe deer: patterns and rates

The aim of this study was to describe the pattern and rates of growth of roe deer fawns up to the age of weaning.

Seasonal variation in coyote feeding behaviour and mortality of white-tailed deer and mule deer

Young ungulates are considered especially susceptible to predation in the initial weeks following birth. However, the timing of mortality can vary depending on the availability of alternative prey and the type of predator, and could vary depending on antipredator defenses used by prey. I used coyote (Canis latrans) scats, observations of coyote hunting behaviour, and mortality data for deer to examine seasonal variation in coyote feeding behaviour and mortality of sympatric white-tailed deer (Odocoileus virginianus) and mule deer (Odocoileus hemionus) fawns. Coyotes captured the vast majority of deer they consumed, forming groups that hunted deer from June through March. Coyotes were observed hunting deer most often in winter when ground squirrels were not available, and an inverse correlation between the amount of deer and ground squirrel in coyote scat reflected this relationship (rs = 0.77, P = 0.004). Fawns of both species had poor survival rates in 1994 (1 of 10 tagged whitetails survived to 1 year, none of 22 mule deer survived), improved survival rates in 1995 (33% of 15 whitetails, 25% of 24 mule deer), and most mortality appeared to be due to coyote predation. The season in which fawns of each species were most vulnerable differed. Tagged whitetail fawns had similar mortality rates in early summer, when they were less than 8 weeks old, as they did in winter, when they were 5-9 months old (35 and 37%, respectively, in 1995). In contrast, mule deer fawns had low mortality rates in early summer (4% in 1994, 17% in 1995), but high mortality rates in winter (100% in 1994, 53% in 1995). Changes in fawn:doe ratios and the examination of carcasses similarly indicated that coyotes captured more whitetails in summer and more mule deer in winter. The seasonal variation in mortality rates of the two species cannot be explained by physical prey characteristics, their relative abundance, or extrinsic factors, and may be due instead to species differences in antipredator behaviour.