Adult Red Deer Research Articles

Divergent age-related changes in parasite infection occur independently of behaviour and demography in a wild ungulate.

As animals age, they exhibit a suite of phenotypic changes, often including reductions in movement and social behaviour ('behavioural ageing'). By altering an individual's exposure to parasites, behavioural ageing may influence infection status trajectories over the lifespan. However, these processes could be confounded by age-related changes in other phenotypic traits, or by selective disappearance of certain individuals owing to parasite-induced mortality. Here, we uncover contrasting age-related patterns of infection across three helminth parasites in wild adult female red deer (Cervus elaphus). Counts of strongyle nematodes (order: Strongylida) increased with age, while counts of liver fluke (Fasciola hepatica) and tissue worm (Elaphostrongylus cervi) decreased, and lungworm (Dictyocaulus) counts did not change. These relationships could not be explained by socio-spatial behaviours, spatial structuring, or selective disappearance, suggesting behavioural ageing is unlikely to be responsible for driving age trends. Instead, social connectedness and strongyle infection were positively correlated, such that direct age-infection trends were directly contrasted with the effects implied by previously documented behavioural ageing. This suggests that behavioural ageing may reduce parasite exposure, potentially countering other age-related changes. These findings demonstrate that different parasites can show contrasting age trajectories depending on diverse intrinsic and extrinsic factors, and that behaviour's role in these processes is likely to be complex and multidirectional.This article is part of the discussion meeting issue 'Understanding age and society using natural populations'.

Biochemical blood profile of red deer (Cervus elaphus), reared in the conditions of Polissya Volyn

It was found that the biochemical parameters of blood of red deer (Cervus elaphus) reared in the conditions of Polissya Volyn, in general, correspond to the main patterns characteristic of this population, although they have some fluctuations. Thus, we have shown that the content of total protein, its fractional composition, concentration of glucose, urea and creatinine in the blood serum of English deer blood line and Latvian crossbreed deer were within the reference values characteristic of this species of wildlife. It was found that the activity of ALT and GGT was higher in animals of English origin, and AST and ALP — in Latvian crossbred deer. The content of Ca, P, Mg and Na ions in the blood was also higher, respectively, by 9.4, 28, 22.7 and 4%. It was found that against the background of stress caused by physical method of capturing animals for blood sampling, the level of total protein and its albumin fraction. The concentration of urea was by 22.5%, glucose — by 18.4% and creatinine by 6.5% higher than in the group of animals with sedation. Under technological stress in deer, the activity of ALT and AST in the blood increases (by 11 and 5.5%) and ALP and GGT (by 9.1 and 20.0%), respectively. The study of blood biochemical parameters in young animals (3–4 months old) revealed that the content of total protein in females is 6.4% higher than in males. At the same time, the activity of AST activity in the blood serum of males was 17.4% higher than in young females. The concentration of Ca ions in males was 32.4% higher than in females, and concentration of P, on the contrary, was lower in males. The ratio of Ca to P in the blood of males was 1.57, and in females — 1.30. It was found that the content of total protein in animals increased with age and was the highest in adult red deer. While the concentration of the studied macronutrients (Ca, P, Na, K) had a higher level in the blood of young animals. While the concentration of the studied macronutrients (Ca, P, Na, K) had a higher level in the blood of young animals.

Occurrence, ecology and management of Fascioloides magna in Bavaria, southern Germany

In 2015, red deer infected with American liver fluke were discovered in the Veldenstein Forest area for the first time. This was the first detection of the fluke in a wild deer population in Bavaria. The aim of the study was to determine the American liver fluke prevalence rates in red deer, roe deer and wild boar in the Veldenstein Forest, as well as factors influencing these rates. Since 2018, the livers of 83% of the red deer culled in the study area have been examined, as well as those of the occasional roe deer and wild boar. The livers are classified by adspection and dissection into four levels of infection. The age of the animals was estimated based on dentition and tooth cementum annuli in the first molar (M1). The livers of 520 red deer, 226 roe deer and 75 wild boar were dissected. All wild boar livers tested negative. 3% of roe deer and 36% of red deer livers were positive. The red deer population was reduced to lower the prevalence, beginning in 2018. In the following years, it fell significantly. Medium and high infection levels were initially detected in 61% of adult red deer. Since 2018, the median number of flukes per infected liver has decreased significantly from 17.51 flukes/liver to 10.0 flukes/liver. On driven hunts, significantly more diseased deer were found than during hunting from raised hides. Furthermore, there are close correlations between the age of the red deer, infections, and the distance from the Pegnitz floodplains. The American liver fluke leads to the extinction of roe deer locally and to a massive infection and decimation of the red deer. Without a drastic reduction in the number of infected deer populations, there is a risk of large‐scale infection of native deer species across Bavaria.

The distribution of strongylid egg and lungworm (Dictyocaulus eckerti) larval counts in adult female farmed red deer (Cervus elaphus), and the implications for parasite control

Whilst healthy adult farmed red deer show little clinical indication of parasite infection, they may still be maintaining infection levels on the farm through low-level shedding of nematode eggs and lungworm larvae. This work was undertaken to establish the long-term distribution of parasite counts, to determine whether the higher counts seen in previous trials are repeatable across the same animals. All adult female red deer on a New Zealand North Island property were faecal sampled (n = 209), weighed, and body condition scored (BCS) on five sampling occasions from March – August 2021. Faecal samples were processed by modified Baermanns to recover, identify, and enumerate lungworm 1st stage larvae (FLC), and nematode faecal egg counts (FEC) were determined by mini-FLOTAC. Between animal variation for FEC was significant (p < 0.001); whilst many counts were low to zero, a few individuals were consistently shedding higher egg counts. Younger animals tended to have higher egg counts (p = 0.003), but there was no association between FEC and BCS (p = 0.22), and FEC and liveweight (p = 0.58). Modelling of the data indicated that 50% of the egg output resulted from 21% of the animals. Additionally, there was no significant association between the higher egg counts and the gastrointestinal nematode classification; ‘long tails’ (likely Oesophagostomum sp.) p = 0.76, and the Ostertagiinae complex p = 0.75. Lungworm counts tended to be very low (0 – 26 lpg); consistent with previous trials and literature in farmed adult deer. However, between animal differences were statistically significant (p < 0.001) indicating some animals were passing more larvae than others, and poorer conditioned animals (BCS 2.5) were significantly associated with higher larval count (p = 0.03). There was no relationship between larval count and age (p = 0.62) and larval count and liveweight (p = 0.22). Modelling indicates that 50% of pasture larval contamination was contributed by 15% of the animals. There was no correlation between nematode egg count and lungworm larvae count (p = 0.22). Adult deer may play an important role as a source of infection for young deer, therefore, an improved understanding of the distribution of infection is needed to improve parasite control.

Neanderthal use of animal bones as retouchers at the Level XV of the Sopeña rock shelter (Asturias, northern Spain)

AbstractBone retouchers are a technological appliance used to perfect lithic tools efficiently. They are most frequently found in Middle Palaeolithic contexts. In this paper, we present a group of bone retouchers from the Mousterian Level XV of the Sopeña rock shelter (Asturias, Spain). The bone part preferred was the middle part of the shaft of long bones: Most of them are on metacarpals, followed by metatarsals, femurs, and tibias. The most used animal species is adult red deer. These retouchers have either one, two, or three active areas, with a central disposition. The impact marks are close together; oval pits are common, as well as straight, sinuous, and irregular grooves. The surfaces on these marks appear pitted and scaled. There are indications that the bones employed were relatively fresh. The length, width, and thickness of those bone fragments seem to be the determining factor when choosing them to be used as retouchers in the process of finishing lithic tools. The formats documented in Sopeña Level XV are similar to those found in other Mousterian sites in Iberia, although there is a certain variability regarding their width. The Neanderthals of Sopeña acquired the raw material for these retouchers from the faunal remains generated in the process of butchering and eating the animals. These retouchers were used as implements to perfect lithic tools made mainly on quartzite, and they were used repeatedly and maybe for a long time.

Coexistence mechanisms of sympatric ungulates: Behavioral and physiological adaptations of blue sheep (Pseudois nayaur) and red deer (Cervus elaphus alxaicus) in Helan Mountains, China

Studying the coexistence mechanisms of sympatric wildlife helps to shed light on why the earth has so many different species. When ungulates share ranges, food and habitat requirements may partially or fully overlap. Therefore, the aim of this study was to determine how sympatric ungulates share limited resources. Carcasses of 27 adult blue sheep (Pseudois nayaur) and three adult red deer (Cervus elaphus alxaicus) were collected in the Helan Mountains, China. Nutritive indices of plant species foraged and morphometric measurements of the digestive system of the two sympatric ungulates were determined. In addition, 120 passive, infrared motion-triggered cameras recorded spatial overlap and temporal overlap between the two species. Camera trapping revealed relatively limited spatial overlap and significantly different activity rhythms between blue sheep and red deer. Differences were also observed in stomach weight, surface enlargement factor of the rumen, and intestine length between the two species. However, the combined relative weight of the stomach and intestine was not different between species. The low spatiotemporal overlap decreased opportunities for encounters between sympatric blue sheep and red deer, and significant differences in digestive systems allowed the two species to consume different plant species or different parts of the same species. Thus, the two sympatric ungulates coexist harmoniously in the Helan Mountains because of long-term evolutionary behavioral and physiological adaptations that eliminate negative effects on the survival of the other species.

Sero-prevalence and risk factors of Toxoplasma gondii infection in wild cervids in Denmark.

Toxoplasma gondii is a zoonotic protozoan parasite capable of infecting possibly all warm-blooded animals including humans, and is one of the most widespread zoonotic pathogens known. Free-ranging wildlife can be valuable sentinels for oocyst contaminated environments, as well as a potential source for human foodborne infection with T. gondii. Here we aimed to determine the sero-prevalence of T. gondii in Danish wild deer populations and examine risk factors associated with increased exposure to the parasite. Blood samples were collected from 428 cervids (87 fallow deer (Dama dama), 272 red deer (Cervus elaphus), 55 roe deer (Capreolus capreolus) and 14 sika deer (Cervus Nippon) from 23 hunting sites in Denmark. The animals were shot during the hunting season 2017/2018, and screened for antibodies against T. gondii using a commercial ELISA kit. One hundred and five (24.5%) cervids were sero-positive. Sero-prevalence was significantly different between species (p < 0.05), with odds of sero-positivity being 4.5 times higher in roe deer than fallow deer, and 3.0 times higher in red deer than in fallow deer. A significant increase in sero-prevalence with age was observed, driven by a significant increase in risk in adult red deer compared to calves (OR: 13.22; 95% CI: 5.96–33.7). The only other significant risk factor associated with wild cervid T. gondii sero-positivity was fencing, with the highest exposure associated with deer from non-fenced hunting areas (OR: 2.21; 95% CI: 1.05–4.99). This study documented a widespread exposure to T. gondii in Danish cervids. Therefore the meat of the wild deer, in particular from roe deer and red deer, should be considered a significant risk of T. gondii infections to humans, if not properly cooked. Further, molecular studies to confirm the presence of infective parasitic stages in the muscles of deer used for consumption is recommended.

First description of Onchocerca flexuosa infections in Danish red deer (Cervus elaphus).

The prevalence of Onchocerca infection in wild cervids from Denmark was studied in 119 fallow deer (Dama dama), 123 red deer (Cervus elaphus), 51 roe deer (Capreolus capreolus) and eight sika deer (Cervus Nippon) shot during the hunting season from October 2017 to January 2018 from 18 geographical locations across Denmark. The carcasses were macroscopic checked for nodules, and skin samples were examined for microfilaria. All roe deer, fallow deer and sika deer were negative for Onchocerca, while 30.9% red deer were positive for either microfilaria, nodules or both. Significantly more adult red deer (50.8%; 37.6-62.4; p<0.0001) were infected with Onchocerca than juveniles <1year (7.8%; 2.1-18.5), while there was an insignificant (p=0.075) difference in prevalence observed between males (17.4%; 7.8-31.4) and females (41.7%; 30.2-53.9). Onchocerca-positive red deer were observed from 91.7% (11/12) of the sampled geographical locations. Species identification was done on adult worms from nodules taken from the lumbar region of 20 red deer of different geographical origin by sequencing the mitochondrial 12S, 16S and nad5 gene fragments. The sequences matched with previously published sequences for Onchocerca flexuosa. The high prevalence of Onchocerca infection caused by O. flexuosa in red deer in Denmark shows that Denmark has favourable vector conditions and a suitable environment for the maintenance of the parasite. To our knowledge, this is the first systematic study of Onchocerca in wild-living cervids in Denmark.

Mother Ranaldi: a post-paleolithic goddess gives birth flanked by supernatural stags

Abstract Birth was one of the most magical, miraculous, and blessed events of post-paleolithic spirituality. The Mesolithic - Early Neolithic rock art paintings of the Ranaldi Shelter (Southern Italy) give distinct visual evidence to a universal subject: the woman during childbirth and the wild animal which, given the context data, is the adult male red deer. The pivotal personage of the drama, Mother Ranaldi, shares her iconographic canon with the Goddess of Childbirth in prehistoric art. She is a majestic, naked, corpulent and fertile anthropomorph who is delivering a new life between her generous thighs. The depiction of the newborn’s head emerging from the vagina emphasizes her female power to procreate. Mother Ranaldi is birthing flanked by two adult stags which she touches with her sacred hands. They are not ordinary animals. Their supernatural nature is described by three features: exaggerated unnatural antlers, clear epiphanic seasonal nature, and bicephalism. They were symbol of worship to the Goddess of Generation, acting as her paredri (supporting, assisting partners). Ranaldi Shelter was used during the seasonal relocation of cervids, which in spring moved from the plains to the summer mountainous ranges. Then, the red paintings had not only a sacred value. Having totemic nature, they carried out a territorial function by contributing to organize and mark the territory, possibly associated with appropriate rituals.

“How not to judge a deer by its cover”: A personality assessment study on captive adult red deer males (Cervus elaphus)

Personality is not a uniquely human characteristic and it has been documented in a wide range of organisms, from mammals to birds, reptiles, fish, and invertebrates. However, personality is still poorly understood in Cervids. Therefore, our study aimed to fill this gap by i) investigating personality and ii) exploring its links to dominance hierarchy, assessed by behavioral observations in 11 captive and tame male red deer (Cervus elaphus). Using questionnaires to assess personality, three trained volunteers rated these animals in 15 behaviorally composed adjectives with detailed descriptions, based on their overall impression at the end of the observation period. Behavioral data from animals were collected across three different situations, namely “feeding” (i.e., high competition for a scarce resource), “normal” (i.e., no external stimuli) in a group setting, and “handling” (i.e., stressful situation due to human manipulation) in an individual setting. We estimated dominance hierarchies between the individuals based on situations of average and high competition (i.e., “normal” and “feeding”) via the Clutton-Brock Index (CBI). Using Fleiss’ Kappa for inter-rater reliability, only five of our 15 behavioral adjectives showed acceptable reliability. Using principal component analysis, four of these adjectives formed one personality component labelled “Confidence/Aggressiveness”. We found that although “Confidence/Aggressiveness” did not correlate with CBI, ratings of two adjectives loading onto this component, namely “Confident” and “Submissive”, significantly correlated with the CBI, indicating that the questionnaire ratings reflect real behavioral variation in red deer males. Our study provides the first assessment of personality in male red deer and adds to the growing literature on Cervid personality, offering the basis for future personality research in ungulates.

Differential diagnosis for a mandibular mass \u2013 a rare case of an odontoameloblastoma in a red deer (Cervus elaphus elaphus)

BackgroundMandibular masses caused by inflammatory processes due to bacterial infections, most common with Actinomyces bovis, are well known in herbivors. This case represents a rare differential diagnosis to common inflammatory processes which cannot be distinguished from neoplasia without detailed histopathological examination.Case presentationA large unilateral mandibular mass of a free-ranging female adult red deer (Cervus elaphus elaphus) was submitted for pathological examination. The animal had been shot due to its poor body condition. Grossly, the mandibular mass showed gingival ulceration and necrosis. Histologically, irregular strands and islands of odontogenic epithelial cells and a matrix of dentin and osteoid-like material were found, leading to the diagnosis of an odontogenic tumor. Considering the animal’s age the tumor was classified as odontoameloblastoma with secondary chronic purulent osteomyelitis.ConclusionsOdontogenic tumors are rare in domestic and wildlife species and so far have not been reported in red deer. In addition to the more common inflammatory processes of the mandibula and other neoplastic diseases of the oral cavity, odontogenic tumors represent a rare differential diagnosis that must be kept in mind especially when masked by inflammatory lesions.

Pyogenic meningitis and trigeminal neuritis secondary to periodontogenic paranasal sinusitis in a red deer (Cervus elaphus).

An adult female red deer died of a severe seizure and dysbasia. Postmortem computed tomography (CT) and magnetic resonance imaging (MRI) were performed. On CT, deciduous right maxillary second and third premolar teeth were observed, and the right infraorbital canal was disrupted. MRI showed that the right trigeminal nerve was enlarged and the right subarachnoid cavity was occupied by fluid and gas. On gross examination, the right paranasal sinus, swollen muscles of the orbit and tonsils, right trigeminal nerve, and right cerebrum surface contained a yellowish-white, cheese-like pus. Based on these findings, the deer was believed to have developed pyogenic meningitis caused by a neuropathic infection secondary to periodontogenic paranasal sinusitis.

Primary ganglioneuroblastoma in a red deer (Cervus elaphus)

We describe the first case of a ganglioneuroblastoma in an adult red deer (Cervus elaphus). This neoplasia showed a unique cervical localisation: it was strongly adhered to the left thyroid...

Nodular onchocercosis in red deer (Cervus elaphus) in Sweden.

The presence of subcutaneous nodular onchocercosis was investigated at slaughter of 151 red deer (Cervus elaphus) (107 juveniles and 44 adults) between October–December 2015. The prevalence of subcutaneous nodules was 56%. Nodules were located in the lumbar region of the back in 96% of the cases, and 38% of the infected red deer had additional parasitic nodules in other body locations, such as rump, thorax, forelimbs and neck. The number of nodules per deer was 1–10 in two-thirds of the affected animals, and only 2% had more than 50 nodules. Significant differences in prevalence of nodule presence were found between adult (81%) and juvenile red deer less than two years of age (45%) (p = 0.0001). Species confirmation and identification was done on 14 randomly selected nodules taken from the lumbar region of 14 deer of different geographical origin, by sequencing the mitochondrial 12S, 16S and nad5 gene fragments. The sequences were more or less identical (12S = 99–100%; 16S = 93–100%; nad5 = 92–100%) to previously published sequences for Onchocerca flexuosa. The high prevalence of nodular onchocercosis caused by O. flexuosa in red deer in Sweden shows that the investigated areas in the southern third of Sweden have favorable vector (simuliids and ceratopogonids) conditions and suitable environment for the maintenance of the parasite. To our knowledge, this is the first systematic study of O. flexuosa in red deer in Sweden.

Morphological and molecular characteristics of six Sarcocystis spp. from red deer (Cervus elaphus) in Spain, including Sarcocystis cervicanis and three new species.

Samples of muscle tissue from the diaphragm, oesophagus and/or heart of eight adult red deer (Cervus elaphus hispanicus) from the Quintos de Mora Park in Toledo, Central Spain, were screened for sarcocysts by means of the compression method. From positive samples, individual sarcocysts were excised and examined in wet mounts under a light microscope (LM) in order to study their basic morphology before being preserved for molecular studies. In all red deer examined, only microscopic sarcocysts were found. Those in the diaphragm and oesophagus were spindle-shaped and about 1×0.1mm in size, while those in cardiac muscle were sac-like and 500-800×80-180μm. By LM, the sarcocysts either had densely packed, about 8-μm-long, hair-like protrusions (type 1), sparsely distributed indistinct projections (fuzzy outline; type 2) or no visible protrusions (smooth surface; type 3). In cardiac muscle, only sarcocysts without visible protrusions were found. One of the latter sarcocysts was examined by scanning electron microscopy (SEM) and found to possess thin ribbon-like protrusions. Forty-eight sarcocysts isolated from the diaphragm, oesophagus and heart of one red deer, as well as 55 sarcocysts from the heart of three other red deer, 103 sarcocysts in total, were characterized molecularly through PCR amplification and sequencing of the partial cytochrome c oxidase subunit I gene (cox1) of the mitochondrial genome, revealing the presence of six major cox1 sequence types. Each type comprised either a single sequence (three types) or a collection of several identical or nearly identical sequences. From selected isolates possessing each of these cox1 sequence types, the complete 18S ribosomal RNA (rRNA) gene was amplified and sequenced directly and/or after cloning of the 5' end half. Supported by the sequence data from the latter gene, as well as the morphology of the sarcocysts from which the sequences originated, the six cox1 sequence types were considered to represent six separate Sarcocystis spp. Two cox1 sequence types were identified as belonging to the previously characterized species Sarcocystis hjorti (one sequence/sarcocyst) and Sarcocystis linearis (38 sequences/sarcocysts), respectively, whereas four sequence types were new. One of the latter types was assigned to the previously named species Sarcocystis cervicanis from red deer, since this sequence type was obtained from 52 sarcocysts from cardiac muscle, which matched the original morphological description (smooth surface) and habitat of this species. The remaining three sequence types were assigned to the three new species Sarcocystis iberica (one sequence/sarcocyst) Sarcocystis venatoria (10 sequences/sarcocysts) and Sarcocystis morae (one sequence/sarcocyst), respectively. The two species S. iberica and S. venatoria shared the same sarcocyst morphology (type 1) and habitat (diaphragm) and had virtually identical 18S rRNA gene sequences, but differed by 4% at cox1, which was considered sufficient to regard them as separate species. The single sarcocyst of S. morae (from the oesophagus) examined by LM had a smooth wall and this species was therefore believed to have the same type of ribbon-like protrusions (ultrastructurally) as sarcocysts of S. cervicanis and S. linearis, which were also the species most closely related to S. morae at cox1. Thus, there seems to be three species with similar ribbon-like cyst wall protrusions in red deer (S. cervicanis, S. linearis, S. morae), as well as three species with similar hair-like protrusions (S. hjorti, S. iberica, S. venatoria). Sarcocysts of S. cervicanis were only identified in cardiac muscle, whereas sarcocysts of S. linearis were found mainly in the diaphragm and oesophagus and rarely in the heart. The relative number of cox1 haplotypes was greater among sequences/isolates of S. linearis (17/38) than among isolates of S. cervicanis (7/52). Four of the species examined (S. cervicanis, S. linearis, S. iberica, S. venatoria) possessed considerable intra-isolate (intra-genomic) sequence variation (insertions/deletions, substitutions) in the 18S rRNA gene.

Social rank and reproductive performance in a herd of farmed red deer females (Cervus elaphus)

Hierarchical relationships between individuals determine unequal access to recourses like food and individuals of the other gender, resulting in a higher reproductive success of high-social ranked individuals. Environmental conditions and food availability may determine how strong these effects are. The aim of this work was to determine if social rank of farmed red deer females affect the reproductive results of a hormonal oestrous synchronisation treatment with ad libitum food. The studied responses included the time to oestrus onset, percentage of females that came into oestrus, conception and calving rates, gestation length, and calf gender. The study was performed during autumn on a research farm located in Mexico (20°36ʹ N, 99°55ʹ W). Forty-nine adult red deer females were assigned to two replications of 21 and 28 animals respectively and were allocated into independent paddocks with ad libitum food and water availability. Oestrous cycles were synchronised with a traditional protocol of intravaginal devices impregnated with progesterone. Agonistic behaviours between females were recorded (total = 1626 interactions), hierarchical position (Success Index = SI) of each animal was calculated and individuals were categorised as high (n = 13), medium (n = 20) or low-ranked (n = 16) individuals. Reproductive data were recorded during the 5 days after the oestrous synchronisation treatment and during the calving period. Any of the recorded responses differ between HR, MR and LR females. Female SI, age and bodyweight were not related with the probability of coming into oestrus, result pregnant, and giving birth to a male calf. Thirty-seven (78.5%) females of this study gave birth. From these calves, 15 were males and 22 were females. Due to high percentage of females in oestrus that gave birth (85.7%), it was not possible to detect the relationship between female SI, age, and bodyweight with the conception rate. Female SI, age and bodyweight were unrelated to time to oestrus onset (r2 = 0.09; P = 0.17), and to gestation length (r2 = 0.10; P = 0.20). In conclusion, with ad libitum high quality food, the social rank of red deer hinds did not affect the time to oestrus onset, percentage of females that came into oestrus, gestation length, calving and conception rates, and offspring sex ratio after an oestrous synchronisation hormonal treatment.

Directional associational plant defense from Red deer (Cervus elaphus) foraging decisions

AbstractThe concept of associational plant defenses is widely accepted and implies that an unpalatable plant can protect its neighbors from grazing. We have investigated the new but similar question of whether a part of a plant, for example, the top or bottom, can protect other parts. At the same time, we investigated whether the previously observed selection of the apical shoot and upper leaves of plants is a direct consequence of food quality (the plant vigor hypothesis) or whether there is an innate or learnt foraging pattern behind the observation. In experiments, we used 1 m high artificial trees, made from aspen branches, and measured red deer browsing from the top (above 0.5 m) and bottom (below 0.5 m), with application of condensed tannin to the top or bottom as a proxy for plant part unpalatability. There were four treatments where either none, both, or one part (top or bottom) of the artificial trees had tannin applied. As expected, we found that red deer consumed less from parts with tannin. We also found that a defended top protected an undefended bottom, but we found no evidence for the opposite relationship, which could be explained by foraging behavior. When examining the behavior, we found that adult red deer prefer to start feeding from the top of a plant. We also found that they spent a shorter time feeding on a defended top. This behavior might cause a defended top to protect an undefended bottom. Such directional associational plant defense could be the result of selectivity with limited flexibility and might be more pronounced for mammalian herbivores than for insects, since mammals are bigger in size and more restricted in their head position. An important applied aspect of these results is that when saplings are protected by adding a repellent, for instance in forestry, it might be enough to apply repellent to the tops. On the other hand, according to this directional associational plant defense, protected bottoms will not protect tops, so newly grown apical shoots may need new protection.

Does Cu supplementation affect the mechanical and structural properties and mineral content of red deer antler bone tissue?

The main factors affecting the mechanical (and other) properties of bone, including antler, are the proportions of ash (especially Ca and P) and collagen content. However, some trace minerals may also play more important roles than would be expected, given their low levels in bone and antler. One such trace mineral is Cu. Here, we studied the effects of Cu supplementation on the mechanical and structural characteristics, and mineral content of antlers from yearling and adult (4 years of age) red deer fed a balanced diet. Deer (n=35) of different ages (21 yearlings and 14 adults) were studied. A total of 18 stags (11 yearlings and 7 adults) were injected with Cu (0.83 mg Cu/kg BW) every 42 days, whereas the remaining 17 (10 yearlings and 7 adults) were injected with physiological saline solution (control group). The Cu content of serum was analysed at the beginning of the trial and 84 days after the first injection to assess whether the injected Cu was mobilized in blood. Also, the mechanical and structural properties of antlers and the mineral content in their cortical walls were examined at three (yearlings) or four (adults) points along the antler beam. The effect of Cu supplementation was different in yearlings and adults. In yearlings, supplementation increased the Cu content of serum by 28%, but did not affect antler properties. However, in adults, Cu supplementation increased the Cu content of serum by 38% and tended to increase the cortical thickness of antlers (P=0.06). Therefore, we conclude that, even in animals receiving balanced diets, supplementation with Cu could increase antler cortical thickness in adult deer, although not in yearlings. This may improve the trophy value of antlers, as well as having potential implications for bones in elderly humans, should Cu supplementation have similar effects on bones as those observed in antlers.

Tuberculosis, genetic diversity and fitness in the red deer, Cervus elaphus

Understanding how genetic diversity, infections and fitness interact in wild populations is a major challenge in ecology and management. These interactions were addressed through heterozygosity-fitness correlation analyses, by assessing the genetic diversity, tuberculosis (TB) and body size in adult red deer. Heterozygosity-fitness correlation models provided a better understanding of the link between genetic diversity and TB at individual and population levels. A single local effect was found for Ceh45 locus at individual level, enhancing the importance of its close functional genes in determining TB presence. At population level, the ability of the red deer to control TB progression correlated positively with population genetic diversity, indicating that inbred populations might represent more risk of deer TB severity. Statistical models also gained insights into the dynamics of multi-host interaction in natural environments. TB prevalence in neighbouring wild boar populations was positively associated with deer TB at both individual and population levels. Additionally, TB presence correlated positively with red deer body size, for which “general and local effect” hypotheses were found. Although body size might be correlated with age, an indirect genetic effect on TB presence could be implied. This study provides new insights towards understanding host-pathogen interactions in wild populations and their relation to fitness traits.

Oral administration of heat-inactivated Mycobacterium bovis reduces the response of farmed red deer to avian and bovine tuberculin

Orally delivered mycobacterial antigens may not sensitize the immunized animals causing a positive tuberculin skin test response. As the first step to address this critical issue, we characterized the response of farmed red deer (Cervus elaphus) to orally delivered heat-inactivated Mycobacterium bovis. Thirty-two adult red deer hinds from a farm known to be free of tuberculosis (TB) were randomly assigned to two different treatment groups, immunized (n=24) and control (n=8). Immunized hinds were dosed orally with 2ml of PBS containing 6×106 heat-inactivated M. bovis. The mean skin test response of immunized deer to both avian purified protein derivative (aPPD) and bovine PPD (bPPD) was consistently lower in immunized than in control hinds. One year after immunization, immunized hinds had a significant reduction in the skin test response to aPPD and in the ELISA antibody levels against both aPPD and bPPD (24–36% reduction; P<0.05). By contrast, no significant change was observed in the skin test response to phytohaemagglutinin, or in the ELISA antibody levels against the M. bovis specific antigen MPB70. The mRNA levels for C3, IFN-γ and IL-1β and serum protein levels for IFN-γ and IL-1β did not vary between immunized and control deer. However, serum C3 protein levels were significantly higher (P=0.001) in immunized than in control deer six months after immunization. These results confirm that oral heat-inactivated M. bovis does not sensitize farmed red deer and therefore does not cause false-positive responses in the tuberculin skin test. The absence of sensitization in orally immunized deer opens the possibility of testing the vaccine in deer and possibly other ruminants without the risk of causing false-positive reactions in TB-tests. This study also provided the first evidence that orally-delivered inactivated mycobacterial antigens elicit some kind of immune response in a ruminant.