Red Deer Hinds Research Articles

Bilateral ovarian teratoma in a free-living Iberian red deer (Cervus elaphus hispanicus)

CASE HISTORY: A 8.5×5.7×5 cm irregularly shaped mass was detected in the location of the left ovary of a 9-year-old Iberian red deer (Cervus elaphus hispanicus) hind shot during a hunting drive. PATHOLOGICAL FINDINGS: On the cut surface, the mass consisted of numerous fluid- or keratin-filled inter-communicating cysts, separated by connective tissue containing solid nodules of dark-coloured foci and hairy skin. The right ovary was of normal size, but contained a 1.5 cm mass of hairy skin and spongy structures. Histologically, the large mass comprised differentiated structures such as cartilage, fibrous connective tissue, smooth muscle, stratified squamous keratinised epithelium, cuboidal multi-layered and respiratory epithelium, clusters of pigment-laden cells, hair follicles, nervous tissue and glandular structures. The hind had a grossly and microscopically normal uterus that contained a 449.5 g female fetus. DIAGNOSIS: Bilateral mature ovarian teratomas. CLINICAL RELEVANCE: This case describes the first known description of an ovarian teratoma in a free-living red deer. The tumour had unique features, such as bilateral presence and concurrency with a normal pregnancy.

201RED DEER (CERVUS ELAPHUS) CALVES BORN FROM IN VITRO-PRODUCED BLASTOCYSTS FERTILIZED AND CULTURED IN DEER SYNTHETIC OVIDUCT FLUID

Deer Synthetic Oviduct Fluid medium (DSOF;; Berg and Asher 2003 Theriogenology 59, 189–205), based upon the composition of red deer oviduct fluid, has been shown to support routine in vitro fertilization and blastocyst development (15%) of in vitro-matured red deer oocytes without the use of somatic cell co-culture or serum supplementation. However, pregnancy establishment and fetal survival remained to be determined. The objectives of this study were to transfer in vitro red deer blastocysts produced by the DSOF culture system, follow fetal survival through calving and investigate trans-cervical embryo transfer for red deer. Red deer hinds of mixed age were synchronized using a 12-day CIDR (Pharmacia & Upjohn, Auckland, NZ) synchrony program (Berg DK et al. 2002 Ani. Reprod. Sci. 70, 85–98). Onset of estrus was synchronized to the day of IVF and embryos were transferred 7 days later. in vitro red deer blastocysts were produced after aspirating oocytes from abattoir-sourced ovaries. Selected COCs were matured and fertilized and presumptive zygotes cultured in vitro (Berg and Asher 2003 Theriogenology 59, 189–205) with modified Ca2+ concentrations: 3.0mM and 1.5mM for early and late DSOF, respectively. in vitro blastocyst development was 14.7% (21/143) on Day 7 and 22.4% (32/143) on Day 8. Ten blastocysts (grade 1 and 2) were selected for transfer on Day 7 (post-IVF) and placed into Emcare embryo holding medium (ICPbio, Auckland, NZ). Blastocysts were loaded into 0.25-cc straws (n=5) or tom cat catheters (n=5) and transported to the Ruakura Deer Unit at 25°C. Hinds were restrained and sedated as described for OPU (Berg and Asher 2003 Theriogenology 59, 189–205) and an attempt was made to pass a cattle transfer pistolette through the cervix. If unsuccessful, the hind underwent laparoscopic uterine transfer. Serial serum progesterone values diagnosed pregnancies at Day 21 and fetal survival was determined using rectal ultrasonography on Day 35, 45, 60 and 90. Seven single-embryo transfers were completed;; 2 of 5 trans-cervical attempts and 5 using the laparoscopic method. Serum progesterone levels confirmed 57% (4/7) of the hinds were pregnant on Day 21;; 2/2 (100%) from trans-cervical and 2/5 (40%) from laparoscopic transfers. No pregnancy losses occurred after Day 21. Four calves, 1 male and 3 female, were born unassisted after 230 to 233 days of gestation. Birth weights ranged from 7.3 to 10kg. Our results indicate that in vitro red deer blastocysts produced using the DSOF culture system can establish pregnancies after transfer and result in normal healthy calves.

Social rank, feeding and winter weight loss in red deer: any evidence of interference competition?

During winter at northern latitudes, large herbivores often exploit patches of concentrated, relatively high quality forage, which may lead to interference competition. The factors affecting success in contests and subsequent dominance rank, such as age and body weight, remain key issues in ungulate behavioural ecology. Maternal effects on offspring body weight are well known, but few studies have investigated if mother's social rank influence offspring rank. Moreover, no study has related dominance rank in ungulates to weight loss during winter. Outcomes of social interactions (n=7,609), feeding time and spatial position in red deer (Cervus elaphus) hinds and calves, and weight loss of calves, were registered from 1981 to 1996 at six winter-feeding sites within the county of Sør-Trøndelag in Norway. The level of aggressiveness was higher among calves than among adult hinds, and the factors determining the outcome of contests also differed. The initiator won the majority of interactions (more than 90% in both hinds and calves). Social rank was related to both age and body weight in adult hinds, and related to body weight and mother rank in calves. The relationship between feeding time and rank was non-linear. Feeding time was correlated with rank only among high ranked hinds, while there was no such relationship among low ranked hinds or calves. There was no correlation between winter weight loss and social rank in calves. Our study therefore underlines that, although frequent aggression is observed at artificial feeding sites of northern herbivores, this is not necessarily sufficient to give rise to interference competition.

Non-Invasive Monitoring of the Adrenocortical Response in Red Deer

To facilitate easy and non-invasive assessment of the stress experienced by red deer (Cervus elaphus), we tested whether adrenocortical function can be monitored by measuring fecal corticoid metabolites. We measured concentrations of a group of cortisol metabolites (3α,11-oxo CM) in the feces of 6 captive red deer hinds before and after an adrenocorticotropic hormone (ACTH) challenge or a control saline injection by enzyme immunoassay (EIA). Results revealed that analysis of fecal cortisol metabolites enabled monitoring of adrenocortical activity. Administration of ACTH resulted in a 6.5 to 20-fold increase in fecal cortisol metabolite levels after approximately 18 hr. Following a planned disturbance, fecal cortisol metabolite concentrations increased 3 to 10-fold in 4 out of 6 individuals. Concentrations of 3α,11-oxo CM were not significantly different in feces collected within approximately 6 hr from defecation as compared to feces sampled immediately after defecation. Thus, fecal corticoid metabolite analysis could be used to evaluate disturbances in farmed red deer, even if immediate sample collection after defecation may not be possible. It also may evaluate stress responses in wild red deer, provided information on the time since defecation is available.

Influence of nutrition and lactation on ovulation and conception in red deer

Reproduction incurs a high energetic cost and failure to meet nutritional needs results in reproductive failure. In red deer hinds, the interaction between nutrition, summer lactation and subsequent ovulation/conception is of particular interest for farmed deer production in NZ due to climatic constraints to summer pasture production in many areas. However, few studies have focussed on the potential perturbing effects of poor nutrition on lactational outputs and potential flow-on effects on ovulation/conception. As lacta tion in red deer naturally persists well beyond the autumn mating period, lactational anoestrus (through hormonal feedback mechanisms) is not a normal feature of the species reproduction. However, lactation is of high nutritional cost to the hind and can potentially exert considerable influence on the incidence and timing of conception via changes in hind liveweight, lipid depots and general body condition. Supporting evidence for this hypothesis is derived from studies of wild red deer within habitats marginal to species survival (e.g. Isle of Rhum, Scotland), where climatic variables greatly influence annual reproductive success of hinds. Under such conditions, even the differences in maternal investment (via lactation) required to raise male and female calves have been demonstrated to influence the subsequent success and timing of conceptions. Studies of farmed red deer in Scotland also demonstrated that hinds on different levels of pasture nutrition during lactation exhibited significant differences in conception date, with earlier conceptions favouring hinds on higher levels of nutrition. There is a growing body of evidence from monitoring of farmed red deer in New Zealand that the interaction between lactation and hind body condition score (BCS)/ liveweight influences subsequent conception rate and date. Recent studies on pre-rut versus post-rut calf weaning practices demonstrated effects of lactation on hind BCS and liveweight, calf growth rates and hind conception dates. These studies highlight the need to better understand the "costs" of lactation on reproductive performance, particularly under conditions of nutritional constraints. Keywords: lactation, nutrition, red deer, reproduction

Winter feeding regimes for 16-22 month old red deer stags and hinds

Farmed red deer (Cervus elaphus) are highly seasonal animals and thus the majority of venison is available during the autumn and winter months. To compete with other red meats, alternative marketing systems for venison need to be developed. Previous ADAS trials have shown that red deer can be finished intensively at 10-12 months of age by extending day length (Davies et al, 1995) but it incurs increased feed costs. An alternative strategy to lower production costs is to reduce growth rates and finish deer at 24-26 months of age. Preliminary trials have shown (Davies and Deakin 1998) that silage only diets, during the second winter, are not sufficient to maintain body weight and a small supplement is required. However the type of supplement needs further investigation. The objective of this study was to examine the effect of feeding high energy and protein diets to yearling deer during their second winter, on winter growth and subsequent performance at grass.

Influence of nutrition during late pregnancy on dam condition, foetal growth and gestation length

Many aspects of the relationship between nutrition and reproductive performance of red deer hinds are poorly understood. One such example is the feed requirements of hinds during the late stages of pregnancy, for which there is considerable diversity of opinion. The present study aimed to relate feed intake of hinds during the last trimester of pregnancy to dam body condition, foetal development and calf growth. Across 3 years, multiparous (n=33) or primiparous (n=18) hinds with known conception dates were housed in individual pens from days 150 to 220 of pregnancy, during which time they were each offered one of three (H, M and L) daily allowances of pelletised rations. Hinds were returned to pasture at day 220 and calving was closely monitored. Liveweight, body condition score (BCS), and lactation score (LS) were recorded weekly from day 150 through to calf weaning at 12 weeks of age. Additionally, hinds in the first year of study underwent CT scans on days 150 and 215 of pregnancy to assess compositional changes of the dam and conceptus. Mean daily ad libitum intakes of H hinds increased from 1.8 to 3.2 kg DM (0.6 to 0.9 MJME/kg0.75) between days 150 and 220. Those of restricted M and L hinds peaked at 1.8 and 1.6 kg DM, respectively, by day 220. This was reflected in significant treatment effects on liveweight gain and change in BCS and LS by calving. CT scans indicated a significant treatment effect by day 215 on the mass of hind tissues and a non-significant trend on conceptus weights. There were no discernable treatment effects on calf birth weights. However, there was an unexpectedly wide spread in calving dates that reflected considerable variation in gestation length. Gestation length was significantly negatively correlated to change in hind liveweight (but not BCS) between days 150 and 220 of pregnancy. Of three neonatal calf mortalities, none were related to dystocia or non-viability. Subsequent growth rates of surviving calves did not reflect prior treatment of their dams, although variation in birth date influenced weights at specific dates. It is concluded from this study that while variation in nutrition of hinds during the last trimester may influence foetal development, variation in gestation length compensates to ensure optimisation of birth weight. Keywords: gestation, nutr ition, pregnancy, red deer

A comparison of the calving behaviour of farmed adult and yearling red deer (Cervus elaphus) hinds

Mortality of newborn red deer (Cervus elaphus) calves is a major concern on New Zealand farms, as perinatal losses average approximately 10% of calves born. Primiparous red deer (calving as yearlings) lose more calves than multiparous hinds (adults). We performed a study on yearling and adult red deer hinds in order to improve knowledge of their calving behaviour and determine any apparent reasons for calf mortality. Pacing along fence lines was observed frequently during the 24h period before birth (individuals were pacing in 43% of observations during this period). Adult hinds had a significantly earlier onset and longer duration of pacing (P<0.05). Hinds were often observed isolated (>20m) from the rest of the herd during the 2 days prior to parturition, and this behaviour was also observed earlier in the adults than in the yearlings (P<0.05). Forty-four percent of adult hinds and 60% of yearlings experienced some form of interference from other hinds during parturition. Among hinds that were interfered with, yearlings had a higher average number of interferences from other hinds during parturition than adults (P<0.05). Calves born to yearling hinds took significantly longer to suckle for the first time (mean=44min) from their dams than calves born to adult hinds (33min; P<0.05). We concluded that an inability of hinds to express natural isolation behaviour was likely to contribute to calf mortality due to increased anxiety (indicated by fence line pacing) and encroachment on the birth areas of others, and that calves of yearlings were at an increased risk of mortality due to the higher number of interferences taking place during parturition and the longer time interval between birth and suckling.

Effects of vaginal Brucella ovis infection of red deer hinds on reproductive performance, and venereal transmission to stags

AIMS: To investigate the effects of vaginal Brucella ovis infection on the reproductive performance of red deer (Cervus elaphus) hinds. To determine whether stags may become infected with B. ovis by venereal transmission from mating infected hinds. METHODS: Thirty mixed-age red deer hinds serologically negative for B. ovis antibodies were synchronised for oestrus on 22 March 2000. B. ovis was inoculated into the vagina of each hind at oestrus and again, 18 days later. At oestrus, hinds were randomly allocated to six groups, each joined with a 16-month-old red deer stag seronegative for B. ovis, for 55 days. Hinds were blood sampled and scanned for pregnancy using rectal ultrasonography at monthly intervals. Six pregnant and four non-pregnant hinds were slaughtered pre-calving and three hinds were slaughtered post-calving. Reproductive tracts and foetuses were examined grossly, histologically and microbiologically. Calves were identified and blood sampled within 3 days of birth. Hinds and calves were blood sampled in February and May 2001 and vaginal swabs were collected from hinds for B. ovis culture. Blood was collected from stags, 5 and 19 days after mating and semen was collected for B. ovis culture. The 17 remaining hinds were mated in 2001 to two mixed-age wapiti (Cervus canadensis) stags. Both stags were blood sampled after mating. Sera were tested in a B. ovis complement fixation test (CFT) and enzyme-linked immunosorbent assay (ELISA). RESULTS: All 30 hinds developed B. ovis antibody levels, measurable using either the CFT or ELISA, but these did not remain elevated. There was no evidence of infection, either by gross pathology, histopathology or microbiological culture in the ten hinds or six foetuses slaughtered pre-calving. All remaining 20 hinds produced normal calves, 15 of which survived until weaning. Three hinds experienced dystocia and gave birth to dead calves and two calves died within 4 days of birth. One hind which had dystocia was euthanased. Samples from this hind and from 3/5 dead calves showed no evidence of B. ovis infection. B. ovis was cultured from the vagina of 1/19 hinds 48 weeks after inoculation, at which time B. ovis CFT and ELISA results for this hind were negative. Most calves had B. ovis serum antibodies at 1–3 days of age but levels were negligible when sampled at 10–15 weeks of age. Foetuses and dead calves were all seronegative. Three of the five red deer stags used for mating in the first year became infected with B. ovis. The two wapiti stags used to mate the remaining 17 hinds the following year remained seronegative. CONCLUSIONS: B. ovis is unlikely to have significant detrimental effects on the reproductive performance of red deer hinds. Venereal transmission via the vagina of hinds is a possible route of transmission between stags. It is possible that survival of the organism in the vagina of some hinds could create difficulties in disease control programmes. CLINICAL RELEVANCE: B. ovis infection of hinds at the time of mating is unlikely to cause significant reproductive losses. Venereal transmission of B. ovis between stags via the hinds may occur when groups of hinds are joined with more than one stag.

A comparison of transvaginal artificial insemination procedures for use in commercially farmed deer

The site of semen deposition (vaginal, cervical or uterine) and the time required for transvaginal artificial insemination (AI) using the Gourley Scope method of AI vs. a standard speculum-guided AI gun was assessed in three species of farmed deer (fallow, red and white-tailed deer). Pregnancy rates using these two transvaginal AI methods were also compared in a commercial herd of fallow does. The estrous cycles of fallow ( n=53), red ( n=27) and white-tailed ( n=27) deer were synchronized using half of a Norgestomet ear implant inserted for 14 days. Following implant removal, does were artificially fix-time inseminated with frozen-thawed semen using either a 0.5 ml standard French-style speculum-guided AI gun or the Gourley Scope method of AI. The time-frame (i.e., duration in minutes) for the AI procedures performed on each animal and the location of semen deposition was recorded. To assess effectiveness of AI, transrectal ultrasonography was conducted in fallow deer 45 days post-AI for pregnancy diagnosis. In fallow does and red deer hinds, use of the Gourley Scope (96.3 and 100%, respectively) enabled a greater ( P<0.05) percentage of intrauterine inseminations compared to the speculum-guided AI gun (73.1 and 42.9%, respectively). In contrast for white-tailed does, both the speculum-guided AI gun and the Gourley Scope resulted in a similar proportion of intrauterine inseminations (92.3 and 100%, respectively). The duration for performing the two transvaginal AI techniques were also similar in red and white-tailed deer. However in fallow does, AI with the aid of the Gourley Scope took longer ( P<0.05) to conduct than the speculum-guided AI gun (6.6±0.72 and 4.3±0.34 min, respectively). The pregnancy rate using both methods of AI combined was overall 32.1% for fallow does. The total percentage of fallow does that conceived with the speculum-guided AI gun was 42.3% whereas the pregnancy rate using the Gourley method of AI was only 22.2% ( P<0.05). Although both AI methods may be acceptable for use in farmed deer, the standard speculum-guided AI gun is simpler and produced more pregnancies compared to the Gourley Scope method in fallow deer, despite a greater proportion of intrauterine inseminations using the Gourley Scope.

Red Deer (Cervus elaphus) Hinds Discriminate Between the Roars of Their Current Harem‐Holder Stag and Those of Neighbouring Stags

During the period of reproduction red deer stags gather harems and roar loudly and repeatedly, both toward competing stags and toward the hinds that they actively herd. It has been proposed that red deer hinds may actively choose their mate on the basis of a comparison of the roaring rate of competing stags. Hinds may also choose to mate with the male that is most familiar to them, i.e. that male who spent most time and effort in retaining them within his harem and in roaring at them. Such a mechanism of female choice implies that females are able to discriminate individual characteristics in the stags’ roars. We investigated this possibility by conducting playback experiments based on the habituation–discrimination paradigm. Our results show that hinds are able to discriminate between the roars of their current harem‐holder stag and those of other neighbouring stags and suggest that this ability, a necessity for individual recognition, may be important in female mate choice in red deer.

Gonadotrophin-induced follicle development in red deer hinds during the breeding and non-breeding seasons

The effect of exogenous equine chorionic gonadotrophin (eCG) and endogenous (GnRH-treatment) gonadotrophins in promoting antral follicle development in red deer hinds was assessed during the breeding and non-breeding seasons. After progesterone pretreatment, hinds received no further treatment, a single injection of 300 iu equine chorionic gonadotrophin or infusion of GnRH (1.0 microg h(-1)) for up to 4 days. Ovaries were recovered (n = 5 per group) at the time of, or 36 h after, progesterone removal. All follicles > or = 2.0 mm in diameter were dissected out, their health status assessed and follicular fluid oestradiol content measured. Granulosa cells were counted and their capacity for oestradiol and cAMP production assessed in vitro. Oestrus, the preovulatory LH surge and ovulation rates were monitored in additional groups of hinds that had been treated identically (n = 5 per group). During the breeding season, all monitored animals ovulated, but five of 15 (one eCG, three GnRH, one progesterone alone) did not exhibit oestrus, and three (all eCG) had luteinized follicles. During seasonal anoestrus, four hinds (all eCG-treated) displayed oestrus, but only two ovulated. Two non-ovulating hinds (one eCG, one progesterone alone) had luteinized follicles. The total number of follicles, or of large (> or = 4 mm) follicles, did not differ significantly between seasons. There were proportionately more healthy follicles during seasonal anoestrus (P < 0.05). Treatment with GnRH, and to a lesser extent eCG, increased the number of oestrogenic follicles and their follicular fluid oestradiol content. In summary, exogenous and endogenous gonadotrophins affected antral follicle development similarly in both the breeding and non-breeding seasons, although the response was variable among animals and often associated with failure of oestrous expression, ovulation and with follicle luteinization.

Gonadotrophin-induced follicle development in red deer hinds during the breeding and non-breeding seasons

The effect of exogenous equine chorionic gonadotrophin (eCG) and endogenous (GnRH-treatment) gonadotrophins in promoting antral follicle development in red deer hinds was assessed during the breeding and non-breeding seasons. After progesterone pretreatment, hinds received no further treatment, a single injection of 300 iu equine chorionic gonadotrophin or infusion of GnRH (1.0 microg h(-1)) for up to 4 days. Ovaries were recovered (n = 5 per group) at the time of, or 36 h after, progesterone removal. All follicles > or = 2.0 mm in diameter were dissected out, their health status assessed and follicular fluid oestradiol content measured. Granulosa cells were counted and their capacity for oestradiol and cAMP production assessed in vitro. Oestrus, the preovulatory LH surge and ovulation rates were monitored in additional groups of hinds that had been treated identically (n = 5 per group). During the breeding season, all monitored animals ovulated, but five of 15 (one eCG, three GnRH, one progesterone alone) did not exhibit oestrus, and three (all eCG) had luteinized follicles. During seasonal anoestrus, four hinds (all eCG-treated) displayed oestrus, but only two ovulated. Two non-ovulating hinds (one eCG, one progesterone alone) had luteinized follicles. The total number of follicles, or of large (> or = 4 mm) follicles, did not differ significantly between seasons. There were proportionately more healthy follicles during seasonal anoestrus (P < 0.05). Treatment with GnRH, and to a lesser extent eCG, increased the number of oestrogenic follicles and their follicular fluid oestradiol content. In summary, exogenous and endogenous gonadotrophins affected antral follicle development similarly in both the breeding and non-breeding seasons, although the response was variable among animals and often associated with failure of oestrous expression, ovulation and with follicle luteinization.

Clonal variation in monoterpene concentrations in Sitka spruce (Picea sitchensis) saplings and its effect on their susceptibility to browsing damage by red deer (Cervus elaphus)

Abstract Damage to young trees as a result of browsing by deer, can lead to significant loss of revenue in commercial forestry plantations. This study investigated the chemical and morphological characteristics of Sitka spruce saplings which influenced their susceptibility to browsing. Specifically, we tested whether genetic variability in monoterpene content of saplings affected deer feeding behaviour. Clonal cuttings of Sitka spruce were grown for 5 years following propagation from 15 parent trees growing on the West Coast of Scotland. Monoterpene concentrations and morphological characteristics of individual saplings were recorded prior to offering them to a group of tame red deer hinds in a series of preference trials, conducted within an experimental enclosure on a moorland site in northeast Scotland. Browsing intensity was assessed after each trial by recording the number of distinct signs of damage on each tree. Results showed that a high proportion of variation in browsing damage could be attributed to inter-trial variability, possibly due to increasing familiarity with the Sitka saplings as the experiment progressed. However, individual saplings were found to differ in their susceptibility to browsing according to predictable criteria: height had a positive influence on browsing damage while monoterpene concentration had a negative influence. The different clones also varied in the amount of damage they received, and between-clone variation in monoterpene concentration was an important factor in explaining variation in preference. These results demonstrate the important genetic influence on susceptibility of Sitka spruce to browsing damage by red deer and suggest that foresters may be able to exploit genetic variation in monoterpene concentrations to improve the resistance of Sitka spruce to deer browsing.

Variation in antral follicle development during the follicular phase of the oestrous cycle in red deer (Cervus elaphus) hinds

The aim of this study was to quantify antral follicle populations in cyclic red deer hinds and to monitor follicle development leading to ovulation. Oestrus was synchronized with exogenous progesterone and ovaries were recovered approximately 0, 12, 24 or 36 h (follicular phase) or 10 days (luteal phase) after progesterone withdrawal (n = 5 per group). All follicles > or = 2 mm in diameter were dissected out, health status was assessed, follicular fluid oestradiol content was measured, granulosa cells were harvested and their capacity for oestradiol and cAMP production was determined. The time of oestrus and the preovulatory LH surge were monitored in five control hinds. Deer ovaries contained 26.6 +/- 3.45 (mean +/- SEM) follicles > or = 2 mm in diameter (range 4-81), with at least one large antral follicle (diameter: 8.3 +/- 0.38 mm) per hind. There was a strong correlation between follicle size and granulosa cell population (r(2) = 0.676). Approximately half (50.7%) of the follicles were classified as healthy, with the percentage classified as atretic decreasing with increasing follicle size. Neither the total number of antral follicles nor their size distribution differed significantly among groups. There were significantly more (P < 0.05) healthy follicles at 24 h after progesterone withdrawal than at 0 h, when large oestrogenic follicles had fewer granulosa cells, lower follicular fluid oestradiol concentrations and lower aromatase activity (P < 0.05) than did those from other groups. In summary, antral follicle development in red deer is similar to that in other monovulatory ruminants, and at least one large follicle is present at all stages of the oestrous cycle.

Variation in antral follicle development during the follicular phase of the oestrous cycle in red deer (Cervus elaphus) hinds

The aim of this study was to quantify antral follicle populations in cyclic red deer hinds and to monitor follicle development leading to ovulation. Oestrus was synchronized with exogenous progesterone and ovaries were recovered approximately 0, 12, 24 or 36 h (follicular phase) or 10 days (luteal phase) after progesterone withdrawal (n = 5 per group). All follicles > or = 2 mm in diameter were dissected out, health status was assessed, follicular fluid oestradiol content was measured, granulosa cells were harvested and their capacity for oestradiol and cAMP production was determined. The time of oestrus and the preovulatory LH surge were monitored in five control hinds. Deer ovaries contained 26.6 +/- 3.45 (mean +/- SEM) follicles > or = 2 mm in diameter (range 4-81), with at least one large antral follicle (diameter: 8.3 +/- 0.38 mm) per hind. There was a strong correlation between follicle size and granulosa cell population (r(2) = 0.676). Approximately half (50.7%) of the follicles were classified as healthy, with the percentage classified as atretic decreasing with increasing follicle size. Neither the total number of antral follicles nor their size distribution differed significantly among groups. There were significantly more (P < 0.05) healthy follicles at 24 h after progesterone withdrawal than at 0 h, when large oestrogenic follicles had fewer granulosa cells, lower follicular fluid oestradiol concentrations and lower aromatase activity (P < 0.05) than did those from other groups. In summary, antral follicle development in red deer is similar to that in other monovulatory ruminants, and at least one large follicle is present at all stages of the oestrous cycle.

Foraging behaviour of red deer Cervus elaphus as a function of the relative availability of two tree species

Cervid populations are rapidly increasing in many part of Western Europe, where they cause damage to forest production. This necessitates a better understanding of what determines their dietary choices. In this experiment, we investigated the relationship between the relative availability of two tree species and diet selection of red deer Cervus elaphus. Three hypotheses were tested: (i) preference for rarity, frequently asserted by foresters, (ii) preference for the more abundant prof- itable species, as predicted by optimal foraging models, and (iii) frequency-independent selectiv- ity, as already observed in moose and roe deer. Six red deer hinds were therefore observed in short- duration tests when offered two plant species, willow Salix caprea and ash Fraxinus excelsior, in varying proportions. The relation between the relative consumption and availability of the two plant species revealed that red deer prefer ash to willow, and that their short-term selectivity is not a fre- quency-dependent process. Individual animals differed in the intensity of their preference, but all reacted similarly to variations in the relative availability of the two plant species. Our results advance our under- standing of the choices of red deer at the feeding site scale, but further research is needed to propose management practices, which would take advantage of their frequency-independent selectivity.

Asymptomatic shedding of Cryptosporidium oocysts by red deer hinds and calves

Levels of Cryptosporidium infection in a group of red deer were monitored over a period of 1 year. Faecal samples were examined on an approximate monthly basis from adult hinds and calves for the presence of Cryptosporidium oocysts. The water–ether sedimentation method followed by sucrose flotation and a monoclonal antibody identification procedure were used. It was found that apparently healthy adult deer were shedding low numbers of oocysts in their faeces throughout the year and that there appeared to be a periparturient increase in the numbers of oocysts shed. Samples taken from 6-month-old deer calves, both in-house and on pasture, had low numbers of Cryptosporidium oocysts, indicating that the calves were also asymptomatically shedding oocysts.

Role of ovarian failure in reproductive senescence in aged red deer (Cervus elaphus) hinds

Physiological and endocrine factors associated with reproductive senescence were assessed in a group of 19 ageing red deer hinds. Reproductive success, defined as the percentage of hinds weaning a calf successfully, decreased gradually from 89% at 6-7 years of age to 50% at 17 years, and subsequently decreased markedly; only one hind reared a calf at 19-20 years of age. When the 12 surviving hinds were approaching 21 years of age, they were compared with ten mature 7-year-old females over the onset of the breeding season. All hinds were subsequently killed, the reproductive tracts were recovered and antral (>/= 2 mm in diameter) and preantral follicle populations were determined by dissection (n = 7 hinds per age group) or stereological analysis (n = 2 ovaries per age group), respectively. Cyclical ovarian activity (plasma progesterone) was evident in fewer aged hinds compared with mature hinds (3/12 versus 10/10, P < 0.001) and mean plasma LH concentrations were higher in aged animals than in mature animals (0.57 +/- 0.05 and 0.20 +/- 0.05 ng ml(-1), P < 0.001). Mean uterine (44.2 +/- 4.5 and 75.4 +/- 4.2 g; P < 0.001) and ovarian masses (0.88 +/- 0.11 and 1.52 +/- 0.12 g; P < 0.001) were lower in the aged hinds, which also had fewer antral follicles than did mature hinds (0.89 +/- 0.35 and 23.5 +/- 4.5 follicles per hind, respectively; P < 0.001). Only one primordial follicle was observed in one of the ovaries of the aged hinds, compared with 7000-21 000 in the ovaries of mature hinds. The high gonadotrophin concentrations, paucity of primordial and antral follicles and failure of ovulation indicate collectively that waning reproductive performance after 17 years of age is primarily due to ovarian failure.

Role of ovarian failure in reproductive senescence in aged red deer (Cervus elaphus) hinds

Role of ovarian failure in reproductive senescence in aged red deer (Cervus elaphus) hinds