Deer Hinds Research Articles

Examining the impacts of red deer hind body condition score and pasture forage mass on calf weaning weight

The effect of pre-calving hind body condition and the interaction with pasture forage mass during lactation on calf growth and intake to weaning were investigated. Two-hundred and forty red deer hinds (Cervus elaphus scoticus × hippelaphus) of average body condition score (BCS) 3.5 were subjected to either ad libitum or restricted feeding for the 4 weeks before the expected start of calving (31 October) to create hinds of low (2.5) or high (3.5) BCS. The hinds were then grazed continuously on pasture of either low (<1200 kg DM/ha) or high (>2400 kg DM/ha) forage mass during lactation (29 October–25 March). In a 2 × 2 crossover design liveweight, liveweight gain and pasture intake were measured in both hinds and calves. Low hind body condition score (BCS 2.5) at the onset of lactation resulted in low calf weaning weight (46.9 kg) when forage mass was low, but not when forage mass was high (57.3 kg). High BCS (3.5) in hinds resulted in intermediate calf weaning weight when on low forage mass (51.2 kg) and high calf weaning weight when forage mass was high (56.6 kg). Both BCS and forage mass influenced calculated total milk production.

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.

Flight distance and reaction to fawn handling are greater in high-than in low-ranked pampas deer (Ozotoceros bezoarticus) females

AbstractThe flight distance from humans and the reaction of the mother to human handling of their offspring are measures that can be used to assess the quality of the human-animal relationship which could vary according to animals’ position in a group. The objective was to determine if the flight distance and the mother's reaction to human handling of her fawn during the first 24 h after birth differ according to pampas deer (Ozotoceros bezoarticus) hinds’ social rank. A complementary aim was to compare the mothers’ reaction to their fawns being handled relative to its sex. Studies were carried out on a semi-captive population. Animals were classed as high- or low-ranking individuals according to agonistic interactions between hinds recorded during autumn (breeding season) while animals received rations. In the first part of the study, the flight distance was determined in high- and low-ranked hinds. In the second, the minimum distance that the mother stayed from her fawn was recorded while the fawn was weighed and sexed during the first 24 h after birth, and the latency period for the dam to return with her fawn was also recorded. High-ranked hinds presented greater flight distance than low-ranked hinds. High-ranked hinds kept a greater distance from their fawns compared to low-ranked hinds and more high-than low-ranked hinds remained at a farther distance. In summary, high-ranked hinds seem to perceive humans as a greater threat, and thus be more fearful of them. The sex of the fawn did not affect the hinds’ reaction to human handling.

Hind genotype influences on lactation and calf growth in farmed red deer (Cervus elaphus)

Multiparous red deer (Cervus elaphus scoticus) hinds (n=18) were artificially inseminated with semen from a red deer stag (n=8) or wapiti bull (C.e. nelsoni) (n=10) to produce red deer or F1 crossbred (C.e. scoticus×C.e. nelsoni) calves. A further seven wapiti×red deer (F1) hinds were artificially inseminated with semen from an unrelated F1 stag to test the hypotheses that (1) crossbred hinds rearing crossbred calves will produce more milk to support calf growth than red deer hinds rearing crossbred calves, and (2) the extra lactation demand of crossbred calves will exert a more detrimental effect on red deer hind live weight and body condition than would occur if the dam was a crossbred hind. Hinds and calves were grazed on ryegrass and white clover pastures and supplemented with pasture silage and barley grain when pasture supply was inadequate. Calves were left with their mothers until approximately 240 days of age. Mean body condition score (BCS) was lower in F1 hinds rearing F2 calves during late lactation (days 150 to 240, P<0.05) than red deer hinds rearing either red deer or F1 calves. F1 calves grew significantly faster than red deer calves and were heavier at all ages, while F2 calves were intermediate. Milk intake of both F1 and F2 calves was higher than red deer calves until day 76 of lactation (P>0.05), but similar thereafter. Male calves had a higher milk intake than female calves at 20 days of age only (P=0.004). The average hind pasture intake was greatest in F1 hinds rearing F2 calves, intermediate in red deer hinds rearing F1 calves and lowest in red deer hinds rearing red deer calves (P=0.038). Total milk output for the lactation increased by approximately 14.6kg/kg average calf live weight at weaning for both F1 hinds rearing F2 calves (P=0.008) and red deer hinds rearing red deer calves (P=0.072), suggesting that calf demand rather than hind liveweight was the key determinant of lactation performance. This was not the case for red deer hinds rearing F1 calves suggesting that there is an upper limit to lactation output depending on hind size. These results do not support the hypothesis that a crossbred hind rearing a crossbred calf will produce more milk than a red deer hind rearing a crossbred calf and provides evidence that the milk production of the hind is primarily driven by milk demand of the calf but has an upper limit depending on the size of the hind. The second hypothesis was not supported as F1 hinds rearing F2 calves exhibited greater loss of body condition score relative to the red deer hinds rearing either red deer or F1 calves in this study. This suggests that the additional energetic demands on a hind from feeding an F1 calf may be met with adequate nutrition.

Do red deer hinds prefer stags that produce harsh roars in mate choice contexts?

Red deer stags give two types of roars during the breeding season, termed ‘common’ and ‘harsh’ roars. This study tested the hypothesis that the characteristic spectro-temporal structure of male harsh roars functions to directly attract females towards male callers during the breeding season. The results show that oestrous hinds look for longer towards speakers broadcasting sequences containing harsh roars, but do not preferentially approach or spend more time in close proximity to speakers broadcasting harsh roars over those broadcasting only common roars. While these observations confirm that the specific acoustic structure of male harsh roars functions to draw the attention of hinds, they are not consistent with the notion that these calls have an immediate impact on mate choice decisions by stimulating oestrous hinds to move towards male callers. Consequently, we suggest that intersexual selection through female mate choice is unlikely to be a major factor driving the evolution of male red deer harsh roars.

The use of GPS data to identify calving behaviour of farmed red deer hinds: Proof of concept for intensively managed hinds

This study investigated the utility of GPS data for assigning individual calving dates and times for red deer hinds based on already known generalised movement patterns around parturition. Nineteen hinds expected to calve in early November were fitted with GPS neck collars two weeks before expected calving. Collars were programmed to log positional data at 5-min intervals over the calving period, with data retrieved at collar removal two weeks after completion of calving. Daily visual observations were conducted to record parturient activity, enabling correlation of actual calving times with GPS-based inferred calving times. Positional data were analysed by a variety of methods to independently assign an inferred calving time, including subjective visual assessment of daily tracking plots, daily core occupational areas (COAs) and ‘distance travelled’ graphics, and an objective assessment based on ‘distance travelled’ graphs using a Hidden Markov statistical model (HMM). All assignments were based on an a priori assumption of four movement states around parturition, with particular emphasis on increased ambulatory behaviour immediately prior to calving followed by a marked reduction in movement at and around the time of birthing. Actual calving time was visually observed to within an hour for 10 hinds, within a day for a further eight hinds, and within a 4-day period for one hind. The subjective graphical measures accurately assigned calving date for the 18 hinds in which actual calving date was known, and assigned a similar date for the remaining hind. The visual assessment of ‘distance travelled’ graphics improved the inference of birth timing to within 7h of actual birthing for the 10 hinds that were actually observed giving birth. The objective assessment of birth timing using the HMM also accurately assigned birth date and constrained the inferred timing to within 9h of actually observed births. Extending the interval between GPS positional recordings increases the length of time that GPS units can function and an analysis of frequency of positional recording indicated that half-hourly observations were still able to allow accurate inference of calving using the HMM approach.

No preference in female sika deer for conspecific over heterospecific male sexual calls in a mate choice context

AbstractMating signals can be used both in contexts of species recognition and mate quality assessment. This study examines species recognition abilities in oestrous females presented with male mating calls from both conspecifics and closely related allopatric heterospecifics. Red deer and sika deer are naturally allopatric polygynous species capable of hybridization during sympatry. Male mating calls are sexually selected and differ greatly between species. Previous work indicated that most but not all oestrous red deer hinds prefer male mating calls from conspecifics over heterospecific sika deer. Using two‐speaker playback experiments, we extend this examination by measuring the preference responses of oestrous sika deer hinds to these stimuli. We predicted that oestrous sika deer hinds will show little flexibility in behavioural responses and prefer conspecific calls over heterospecific calls, similar to those of red deer hinds. In contrast, sika deer hinds showed high levels of flexibility and no difference in overall preference behaviours, suggesting that vocal behaviour does not provide a solid barrier to hybridization in this species. The asymmetry in heterospecific preference responses between these species is discussed in relation to possible causation and hybridization patterns observed in free‐ranging populations.

Sex and age-class differences in calls of Iberian red deer during the rut: reversed sex dimorphism of pitch and contrasting roars from farmed and wild stags

Stag rutting calls differ among subspecies of red deer Cervus elaphus. Studying sex-, age-, and subspecies-related vocal variation may highlight the forces driving this evolution. This study presents the first bioacoustical comparison of oral calls produced during the rut by Iberian red deer Cervus elaphus hispanicus stags, hinds and calves and compares the acoustics of nasal and oral calls of hinds and calves. Also, it provides the first comparison of rutting roars between farmed and wild stags. Call maximum and mean fundamental frequencies (f0max and f0mean) were higher in farmed than in wild stags. Moreover, hinds had lower f0max and f0mean compared with both farmed and wild stags. The call minimum fundamental frequency (f0min) was indistinguishable between all groups of adults, irrespective of sex, farming and nasal versus oral vocal emission. In calves, but not in hinds, oral calls had higher f0max and f0mean compared with nasal calls. The higher fundamental frequencies in farmed as compared with wild stags may have resulted from emotional arousal due to human presence at recordings or from the higher body conditions of stags reared under a farm. The comparison of our results with previously published data on various subspecies of red deer suggests that there are different pathways of vocal ontogeny in eastern and western branches of Cervus elaphus and that the acoustics of stag and hind calls are more similar within the various subspecies than they are among the subspecies.

The relationship between body-mass and puberty in young red deer (Cervus elaphus) hinds: Evidence of early-life effects on permissive live-weight thresholds

This study, based on the analysis of growth and reproductive records of 6158 young red deer hinds, tested the hypothesis that the nutritional environment in early life influences the permissive body mass threshold for puberty at around 16 months of age. Live-weight at 3 months (i.e. weaning weight) was a proxy for their nutritional environment between birth and weaning, live-weight at 14 months was the indicator of pre-mating body mass, and pregnancy status at 18–19 months was a proxy for entry into puberty. Data were obtained for two sub-populations of hinds, the commercial stud herds, across four consecutive years. The modelled relationships between pre-mating live-weight and the predicted pregnancy rate demonstrated between-year variation for the logistic curves for the commercial herd for the live-weight range from 50 to 90kg (P<0.001). For the stud herd, the predicted pregnancy rate at any given live-weight did not vary significantly between years (P>0.05) and the pregnancy rates for live-weights <90kg were higher than for the commercial herd. The regression of average weaning weight on probability of pregnancy showed significant positive associations (P<0.05) at 60kg, 70kg and 80kg (R2=0.513, 0.517 and 0.439, respectively). There were no significant regressions at pre-joining live-weights at 90kg or above (P>0.05). The study supports the central hypothesis of early-life influences on the permissive body mass threshold for entry into puberty.

Clinical chemistry of farmed red deer (&amp;lt;i&amp;gt;Cervus elaphus&amp;lt;/i&amp;gt;) yearling hinds reared on grass or &amp;lt;i&amp;gt;papillonaceous&amp;lt;/i&amp;gt; pasture paddocks in Hungary

Abstract. Yearling red deer (Cervus elaphus) hinds of identical initial body weight were reared on a monocotyledonous grass (group 1) or on a papillonaceous plant pasture (group 2) for 212 days. At the end of the experiment (when deer were shot) blood was taken from ten animals of each group for serum biochemical analysis. Hinds of group 2 provided higher final body weight (90±3.5 vs. 101±6.6 kg) and higher daily body weight gain (105.7±10.7 vs. 153.8±26.8 g/day). Within serum nitrogenous compounds group 2 provided higher total protein concentrations, while from the lipids only serum triglyceride levels were higher in this group. Serum potassium was in both groups higher than the reference range with a superposed slight hyperkalaemia in group 2. Higher lactate dehydrogenase and alkaline phosphatase activities were found in group 2 and lower aspartate aminotransferase activity values. Inorganic phosphate concentration showed a significant difference (group 1 provides higher values). Results refer to an expressed venison growth as a result of the rich dietary protein supply of group 2. Findings were evaluated as well with discriminant factor analysis, outlining the relative importance of the single blood biochemical parameters in shaping the inter-group differences.

Influence of calf genotype on dam lactation and calf growth in farmed red deer (Cervus elaphus)

Multiparous red deer (Cervus elaphus scoticus) hinds (n=17) were either mated to a red deer stag or artificially inseminated with semen from a wapiti bull (C.e. nelsoni) to produce red deer or F1 crossbred (C.e. scoticus × C.e. nelsoni) calves to test the hypotheses that (1) red deer hinds rearing crossbred calves will produce significantly more milk to support calf growth than hinds rearing red deer calves, and (2) hind live weight and body condition may suffer as a result. Hinds and calves were grazed on ryegrass and white clover pastures and supplemented with pasture silage and barley grain when pasture supply was inadequate. Calves were left with their mothers until 9–10 months of age when lactation had terminated naturally. Mean body condition score (BCS) loss was greater in hinds rearing F1 calves than in hinds rearing red calves in the period from late gestation to mid-lactation (September–March, P<0.05). F1 calves grew significantly faster than red deer calves and were heavier at all ages. From February onwards there was a consistent decline in milk intake, and by the latest measurement (22 July) milk production was negligible, and most hinds had ceased lactating. Milk intake by the F1 calves was significantly greater until day 114, after which the measured milk intake was not significantly different. Pasture intake of the F1 calves was significantly greater at day 114 but not at other times (P<0.05). The average hind pasture intake was also not significantly affected by calf genotype when adjusted for post calving hind live weight. The results support the hypothesis that a red deer hind rearing an F1 calf produces significantly more milk than a hind rearing a red deer calf, suggesting that the growth of a red deer calf is limited by its milk demand rather than milk supply by the hind. The study also supported the second hypothesis. Hinds rearing F1 calves exhibited greater losses of body condition score relative to the hinds rearing red deer calves, indicating that the hinds rearing F1 calves were in a greater negative energy balance that hinds rearing red deer calves. This highlights the additional energetic demands on a hind from feeding an F1 calf and in a farmed context the need to ensure that adequate nutrition is provided.

Effects of feed supplementation on mineral composition, mechanical properties and structure in femurs of Iberian red deer hinds (Cervus elaphus hispanicus).

Few studies in wild animals have assessed changes in mineral profile in long bones and their implications for mechanical properties. We examined the effect of two diets differing in mineral content on the composition and mechanical properties of femora from two groups each with 13 free-ranging red deer hinds. Contents of Ca, P, Mg, K, Na, S, Cu, Fe, Mn, Se, Zn, B and Sr, Young’s modulus of elasticity (E), bending strength and work of fracture were assessed in the proximal part of the diaphysis (PD) and the mid-diaphysis (MD). Whole body measures were also recorded on the hinds. Compared to animals on control diets, those on supplemented diets increased live weight by 6.5 kg and their kidney fat index (KFI), but not carcass weight, body or organ size, femur size or cortical thickness. Supplemental feeding increased Mn content of bone by 23%, Cu by 9% and Zn by 6%. These differences showed a mean fourfold greater content of these minerals in supplemental diet, whereas femora did not reflect a 5.4 times greater content of major minerals (Na and P) in the diet. Lower content of B and Sr in supplemented diet also reduced femur B by 14% and Sr by 5%. There was a subtle effect of diet only on E and none on other mechanical properties. Thus, greater availability of microminerals but not major minerals in the diet is reflected in bone composition even before marked body effects, bone macro-structure or its mechanical properties are affected.

Voluntary food intake of pregnant and non-pregnant red deer hinds

Efficient farmed venison production under New Zealand lowland conditions requires early calving to better align lactation with pasture availability. However, hinds that conceive early in the breeding season have a longer gestation length than those conceiving later, negating some of the gains achieved by early conception. This variation in gestation length may relate to seasonal imbalances in hind nutrient uptake influencing foetal growth. However, little is known about food intake cycles of pregnant hinds and whether they exhibit the photoperiod-induced voluntary food intake (VFI) reduction over winter seen in younger age classes and adult stags. This study investigated the effect of pregnancy status on VFI of red deer hinds. In addition, concentration of leptin and ghrelin circulating in the body was measured throughout the study to ascertain if these hormones are indicative of hind energy status. Seven pregnant (P) and seven non-pregnant (NP) hinds were housed indoors in individual pens from April to November where they were offered daily an ad libitum pelleted ration. On average, P hinds gained 75g/day and NP hinds lost 27g/day (P=0.02) in autumn. Mean live weight (LW) of both groups then steadily increased for the remainder of the study with no significant difference between groups. Mean body condition score (BCS) change of P and NP hinds was similar in autumn and winter, but whereas that of P hinds decreased in spring, that of NP hinds increased (P=0.02). Pregnancy status of the hinds had no significant effect on mean VFI throughout the trial except for the last 5 days before parturition when VFI of P hinds decreased dramatically (P=0.001). VFI of both groups of hinds was significantly higher in autumn (P=0.03) and spring (P=0.01) than in winter and for every 0.1MJME/kgLW0.75/day increase in mean VFI during the study period, gestation length decreased by 6.4 days (r2=0.51; P=0.04). Pregnancy status had no significant effect on plasma concentration of either leptin or ghrelin at any of the sampling times and there was no significant association of either leptin or ghrelin with VFI. However, leptin plasma concentration was positively associated with BCS (r2=0.41; P=0.008). This study showed that VFI of pregnant hinds was depressed during winter and early spring, and was negatively associated with gestation length. A reduction in BCS of pregnant hinds indicated that they were in a moderate energy deficit during the final third of gestation.

Optimizing the sampling effort to evaluate body condition in ungulates: A case study on red deer

Body condition is a useful measure of the nutritional status and performance in ungulates. The most widely used indicators of body condition are based on fat reserves, mainly those surrounding the kidneys. To estimate the body condition in large herbivores, researchers often collect and pool the data from both kidneys and their perirenal fat in order to compensate for potential differences between the body condition indicators obtained from the left and right kidneys. Since these differences do not seem to be properly established in wildlife, we checked for the potential differences between the body condition indicators, derived from both kidneys, in wild ungulates. In the present study, we used red deer Cervus elaphus, both under experimental and field conditions, as a model to analyse the patterns of response of the body condition indicators, calculated from left and right kidneys, to supplementary feeding, sex, age class and season. By considering two analytical approaches – kidney fat index and fat weight (including kidney weight as a covariate) – we consistently obtained similar statistical results and the same ecological interpretations by using left, right and average indicators for all the factors tested. In the experimental study, supplementary feeding had a significant effect on all the body condition indicators of red deer hinds. Under field circumstances, the condition indicators were statistically higher in females than in males and they increased with age. Sex related differences were significant in the winter. Taking into account our results, we hypothesize that information from only one kidney will be enough to assess the body condition in red deer and probably in other wild ungulates. However, a standardized sample (i.e. always using the same kidney and associated fat) should be used, while a better understanding regarding possible asymmetries in the amount of the energy reserves on each side of the animals’ bodies has not been reached. Our study has clear implications concerning wildlife monitoring since it represents a considerable reduction of time and effort, both in the field (collecting the samples) and in the laboratory (processing and weighing the samples) when evaluating the body condition of individuals and populations.

Assessment LOPU-IVF in Japanese sika deer (Cervus nippon nippon) and application to Vietnamese sika deer (Cervus nippon pseudaxis) a related subspecies threatened with extinction

In mammals, recovery of oocytes by laparoscopic ovum pick-up (LOPU) coupled with in vitro production (IVP) of embryos represents a promising strategy for both amplification and genetic management of sparse animals from captive endangered wild species. As integrated technique developed mainly for domestic livestock, LOPU-IVP requires several studies to set up protocols for follicular stimulation or optimization of IVP before envisaging successful transposition to wild species. In deer, many endangered subspecies would be potentially concerned by applying such an approach using common subspecies for protocols optimization. The aim of the present study was to assess efficiency of follicle stimulation using ovine FSH (oFSH) for recovery of oocytes by LOPU in common sika deer (Cervus nippon nippon) before transposition of an optimized methodology for IVP of embryos from endangered Vietnamese sika deer hinds (Cervus nippon pseudaxis). In common sika deer, two doses of oFSH (0.25 and 0.5 U) and two frequencies of administration (12 and 24 h) were compared by monitoring of subsequent ovarian response, quality of oocytes recovered by LOPU, and in vitro developmental competence. In a first experiment, the dose of oFSH administered did not significantly affect the total number of follicles aspirated per hind per session (8.6 ± 1.0 vs. 8.2 ± 1.6 with 0.5 vs. 0.25 U oFSH, respectively; not significant). In a second experiment, frequency of 0.25 U oFSH administration did not affect ovarian response. Efficiency of IVP determined on blastocysts rates after in vitro maturation, fertilization, and development in oviduct epithelial cells coculture was increased when FSH was administered at 12-h intervals. Immune response after several follicular stimulations was detected against exogenous oFSH in plasma from the majority of sika deer hinds but was not associated with decreased ovarian response. When 0.25 U oFSH was administered at 12-h intervals to Vietnamese sika deer (N = 4), good quality cumulus oocyte complexes with complete and compact cumulus investments were recovered allowing a high cleavage rate after in vitro maturation and fertilization. Development to the blastocyst stage occurred in a high proportion (30% of oocytes) after coculture with ovine epithelial cells allowing cryobanking of transferable embryos from Vietnamese sika deer. These results confirm that LOPU-IVF after ovarian stimulation with oFSH may be a successful tool for cryobanking transferable embryos from endangered sika deer subspecies.

Global gene expression analysis in skin biopsies of European red deer experimentally infected with bluetongue virus serotypes 1 and 8

Bluetongue virus (BTV) is a double-stranded RNA virus transmitted by blood-feeding biting midges of the genus Culicoides to wild and domestic ruminants, causing high morbidity and variable mortality. The aim of this study was to characterize differential gene expression in skin biopsies of red deer (Cervus elaphus) hinds experimentally infected with BTV serotypes 1 and 8. Skin biopsies were collected from BTV-1 and BTV-8 experimentally infected and control hinds at 14 and 98 days post-infection (dpi). Global gene expression profile in response to BTV infection was characterized at 14dpi using a bovine microarray together with real-time RT-PCR analysis of differentially expressed genes at 14 and 98dpi. Eighteen genes were upregulated and three were downregulated in response to virus infection, with no significant differences between BTV-1 and BTV-8 infected hinds. Seven unique genes, six upregulated (ISG15, PSMB8, PSMB9, BOLA, C1qA, C4) and one downregulated (FOS) were over-represented after conditional test for biological process gene ontology, which affected five molecular pathways (RIG-1, proteasome, MHC-1, complement, TLR) implicated in host immune response. BTV infection had a minor and transient effect on gene expression in hinds, as shown by the very few genes that were differentially expressed in response to infection at 14dpi, most of which had similar expression levels between infected and uninfected animals at 98dpi. These results suggested that red deer could control BTV infection with little effect on host molecular pathways.

Benefits for dominant red deer hinds under a competitive feeding system: food access behavior, diet and nutrient selection.

Social dominance is widely known to facilitate access to food resources in many animal species such as deer. However, research has paid little attention to dominance in ad libitum access to food because it was thought not to result in any benefit for dominant individuals. In this study we assessed if, even under ad libitum conditions, social rank may allow dominant hinds to consume the preferred components of food. Forty-four red deer hinds (Cervus elaphus) were allowed to consume ad libitum meal consisting of pellets of sunflower, lucerne and orange, and seeds of cereals, corn, cotton, and carob tree. The meal was placed only in one feeder, which reduced accessibility to a few individuals simultaneously. During seven days, feeding behavior (order of access, time to first feeding bout, total time spent feeding, and time per feeding bout) were assessed during the first hour. The relative abundance of each meal component was assessed at times 0, 1 and 5 h, as well as its nutritional composition. Social rank was positively related to the amount of time spent feeding during the 1st h (P = 0.048). Selection indices were positively correlated with energy (P = 0.018 during the 1st h and P = 0.047 from 1st to 5th) and fat (only during the 1st h; P = 0.036), but also negatively with certain minerals. Thus, dominant hinds could select high energy meal components for longer time under an ad libitum but restricted food access setting. Selection indices showed a higher selectivity when food availability was higher (1st hour respect to 1st to 5th). Finally, high and low ranking hinds had longer time per feeding bout than mid ones (P = 0.011), suggesting complex behavioral feeding tactics of low ranking social ungulates.

Application of commercial enzyme linked immunosorbent assays (ELISA) for the detection of antibodies for foot-and-mouth disease virus in wild boar and red deer

For detecting antibodies towards foot and mouth (FMD) virus in sera collected from red deer hinds (Cervus elaphus) and wild boars (Sus scrofa), three commercially available enzyme- linked immunosorbent assays (ELISA) were used. Two ELISA kits (PrioCHECK FMDV NS and CHEKIT FMD-3ABC) were used for the detection of antibodies towards non-structural proteins of FMD virus and one assay was based on the detection of antibodies for serotype O (PrioCHECK FMDV type O). All of the sera tested in our study were negative for antibodies against FMD virus. The aim of this study was to investigate the usefulness of commercially available ELISA kits given for marketing authorization in Croatia in testing the prevalence of FMD antibodies in wild boar and red deer populations. Since the producers of ELISA kits used in our study did not declare wild animals as a target species, we hypothesised that the same kits could be used for serological diagnosis of FMD in red deer and wild boars. Our study confirmed that the kits used are acceptable for detecting antibodies in both species tested, however, the investigation highlighted the problem of validating the kits due to the absence of available positive sera originating from red deer as well as other susceptible species, especially artiodactyls.

Pre-weaning growth of red deer calves is not determined by ability of hinds to produce milk

Three experiments were carried out to determine whether growth of suckling red deer calves is determined by the potential of their mothers to produce milk. In the first experiment red deer hinds (n = 10, calves 6 weeks old) were treated either with bovine somatotrophin (bST, 54 mg s.c. injected every 2 weeks for 8 weeks then 108 mg every 2 weeks for a further 8 weeks) or saline. There was no effect of bST treatment on calf or hind liveweight, calf liveweight gain or body condition score of hinds. The second experiment used red and red-wapiti crossbred deer calves (n = 8–11) suckled by red deer dams that had been treated with bST or had received excipient only for 12 weeks from when the calves were 5 weeks old. Calf liveweight was affected by genotype (wapiti-red crossbreds were heavier than their red counterparts) but there was no effect of bST treatment of the hinds on calf growth in either of the genotypes. Although bST treatment of the suckled hinds elevated their plasma insulin-like growth factor-1 concentration it had no effect on milk yield. A third experiment ruled out the possibility that bST ingested by calves in milk from treated hinds would have had any influence on growth of calves in the other experiments. From these results it is concluded that the inherent demand from suckling calves, rather than the ability of adequately nourished hinds to produce milk, determines growth rate of red deer calves from birth to weaning.

Steroid hormones profile during an ovarian synchronization procedure in different age categories of red deer hinds (Cervus elaphus L.)

The objective of the present study was to compare estradiol/progesterone ratios of different age categories of red deer hinds and use it as a predictor of estrus synchronization success and consequently conception rate. To accomplish this we used 38 red deer hinds to establish serum progesterone and estradiol levels in young (21 animals), mature (10 animals) and old (7 animals) hinds during the estrus synchronization procedure (transvaginal/cervical AI). The following estrus synchronization was used: at the start of the experiment each hind received a controlled intravaginal drug-releasing device (CIDR, Pharmacia&Upjohn, New Zealand) containing 0.3 g of progesterone. The device was removed on day 11, simultaneously with an application of 250 IU of Pregnant Mare Serum Gonadotropin (PMSG, Folligon® Intervet International, Boxmeer, Holland). Transvaginal/ cervical AI (artificial insemination) was performed 48 hours after CIDR withdrawal (day 13). Blood samples were obtained from the jugular vein using a Venoject® vacutainer without an anticoagulant for hormonal tests on the same experimental day (0, 11th and 13th day). A statistically (p<0.01) higher progesterone level was found in young hinds on the 11th day after controlled intravaginal drug-releasing device insertion. A significantly higher (p<0.01) estrogen level was observed in the young in regard to mature and old hinds on the expected day of estrus (13th day). Estradiol/progesterone ratios showed a statistically significant difference (p<0.01) on insemination day (13th day) between old and young hinds (98.67 : 46.59) and between old and mature hinds (98.67 : 51.79). Out of a total of 38 hinds only 9 had their offspring, 6 of the young and 3 of the mature hinds.