Deer Hinds Research Articles

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

Genetic influences on reproduction of female red deer (Cervus elaphus) (2) seasonal and genetic effects on the superovulatory response to exogenous FSH.

This study evaluated the influences of seasons and genotype on the superovulatory response to a standardised oFSH regimen in red deer (Cervus elaphus scoticus) and its hybrids with either wapiti (C.e. nelsoni) or Père David's (PD) deer (Elaphurus davidianus). Adult red deer (n=9), F(1) hybrid wapiti x red deer (n=6), and maternal backcross hybrid PD x red deer (i.e., 14 PD hybrid; n=9) were kept together in the presence of a vasectomised stag for 13 months. At 6 weekly intervals, all hinds received a standardised treatment regimen used routinely to induce a superovulatory response in red deer hinds, with 10 consecutive treatments spanning an entire year. This involved synchronisation with intravaginal progesterone devices and delivery of multiple injections of oFSH (equivalent to 72 units NIH-FSH-S(1)). Laparoscopy to assess ovarian response was performed 6-7 days after the removal of the devices. Both season and genotype had significant effects on ovulation rate (OR) and total follicular stimulation (TFS) (P<0.05). For all the three genotypes, ovarian responses were highest from March to November (breeding season) and lowest in the period from December to January, inclusive. Mean OR for red deer hinds ranged from 3.7 to 1.8 during the breeding season, with no observable trend. All red deer hinds were anovulatory during December and January. A similar pattern occurred for 14 PD hybrids, although mean OR during the breeding seasons were twofold lower than for the red deer. For F(1) wapiti hybrids, the first two treatments in March and April resulted in the highest mean OR observed (15.6 and 11.7, respectively). Thereafter, mean values ranged between 6.3 and 4.7 for the remainder of the breeding season. Furthermore, mean OR of 3.0 and 0.5 were recorded in December and January, respectively. For the red deer and F(1) wapiti hybrids, between-hind variation in OR was not randomly distributed across the treatment dates, indicating that the individuals varied significantly in their ability to respond to oFSH, at least within a given season.In conclusion, the study has shown that relative to red deer, F(1) wapiti hybrid hinds exhibit a higher sensitivity to oFSH, whereas 14 PD hybrid hinds have a lower sensitivity. However, individual variation within genotype was very marked. A seasonal effect was apparent for all genotypes, although some F(1) wapiti hybrid hinds exhibited ovulatory responses throughout the year.

Milk production and composition in captive Iberian red deer (Cervus elaphus hispanicus): effect of birth date.

This study describes milk production and milk composition of Iberian red deer (Cervus elaphus hispanicus) females (hinds) and the effect of calving date and BW change of hinds by milking over 34 wk. All hinds produced milk throughout the 34-wk study period, well over the standard lactation period. Total milk yield was 224.1 +/- 21.1 L, and daily production was 0.91 +/- 0.06 L. Milk yield decreased with lactation stage (P = 0.01) and the later a calf was born (P = 0.008), and it was greater in posterior quarters (P < 0.05). Milk yield was unaffected (P > 0.10) by side position or milking order of the udder. Milk production did not correlate with hind BW (P > 0.1). Hinds lost 4.4% BW during lactation (P < 0.001); losses increased the later a calf was born (P = 0.012). Iberian red deer milk had 11.5% fat, 7.6% protein, 5.9% lactose, and 26.7% DM. Stage of lactation affected fat (P < 0.001), protein (P = 0.002), DM (P < 0.001), and protein:fat ratio (P < 0.001), but not lactose (P > 0.1). These constituents became concentrated as lactation proceeded, and protein was substituted by fat. Calving date had a similar concentrating effect on fat (P < 0.001) and DM (P < 0.001), whereas it decreased lactose (P = 0.015) and protein (P = 0.002), thus producing a substitution of protein by fat (ratio of protein to fat, P < 0.001). Milking order of quarters or their position had no effect on milk composition (P > 0.10). Results suggest that milk production and milk energetic quality might increase by advancing calving date in red deer hinds.

The relationship between habitat choice and lifetime reproductive success in female red deer.

In non-territorial species, individuals can move freely and should be distributed in an ideal free manner between habitats and areas with respect to resources that influence lifetime reproductive success (LRS). Consequently, no relationship between diet quality and LRS should be expected. However, there have been no attempts to test this prediction. The present paper investigates the relationship between forage habitat use and LRS in red deer (Cervus elaphus) hinds within three neighbouring areas on the Isle of Rum which differed in their amounts of high-quality-forage habitat. Within areas, hinds move widely and have access to the same resources. We found no correlation between LRS of individual hinds and their use of high-quality-forage habitat (i.e. short Agrostis/Festuca grassland). Our analysis suggests that high hind densities on short Agrostis/Festuca grassland offset any advantages of increased access to preferred forage. These results support the hypothesis that red deer hinds are distributed in an ideal free manner with respect to the use of high-quality-forage habitat. However, hinds rarely leave areas where they are born, and the analysis suggests that constraints in changing areas hindered an ideal free distribution on a larger spatial scale. Consequently, mean LRS was not the same within the three investigated areas: one area, with a low amount of short Agrostis/Festuca grassland and a low hind density, contributed more male offspring (and more total offspring) per hind to the population than the other two areas.

Source and site of action of anti-luteolytic interferon in red deer (Cervus elaphus): possible involvement of extra-ovarian oxytocin secretion in maternal recognition of pregnancy.

Six conceptuses were collected from red deer hinds on day 22 after synchronization of oestrus with intravaginal progesterone-releasing devices (removal of device = day 0). Within 24 h of culture in vitro, the supernatant from five of six conceptuses showed detectable antiviral activity. Interferon alpha (IFN-alpha) receptors were identified by immunohistochemistry on the luminal surface of the endometrium, in the neurohypophysis and paraventricular hypothalamus, but not in the ovaries of the hinds from which the conceptuses were collected. Another 16 intact hinds were synchronized as above. Injection of 4 mg IFN i.m. twice a day on days 13-15 had no effect on cloprostenol-induced oxytocin secretion on day 15 and did not prevent cloprostenol-induced luteal regression. Sixteen ovariectomized hinds received a protocol of steroid treatment to mimic ovarian hormone secretion during the normal oestrous cycle. On day 16, hinds showed undulant oxytocin secretion that showed a degree of temporal association with uterine PGF2 alpha release. Treatment with 4 mg IFN-alpha I 1 twice a day on days 13-16 had no effect on this spontaneous oxytocin secretion, but reduced the magnitude of cloprostenol-induced oxytocin secretion on day 17 (P < 0.05). These results indicate that red deer conceptuses secrete an anti-luteolytic IFN to which the endometrium expresses a receptor during early pregnancy. The presence of IFN receptors in the hypothalamus and posterior pituitary and the IFN-induced suppression of extra-ovarian oxytocin secretion provides tentative evidence of an involvement of the central nervous system in maternal recognition of pregnancy in deer.

Stag exposure advances the lh surge and behavioral estrus in eld's deer hinds after cidr device synchronization of estrus

The impact of male presence or absence on the timing of the preovulatory LH surge and estrus was studied in 3 experimental groups (n = 6/group) of Eld's deer hinds pretreated with intravaginal progesterone-releasing devices (CIDR-type G) as follows: Group 1 = indirect male contact barn; Group 2 = direct male contact barn; and Group 3 = male isolation barn. For all hinds, the duration of the preovulatory LH surge averaged 2.5 ± 0.5 h, whereas mean peak preovulatory and basal LH concentrations were 2.9 ± 0.2 ng mL 1 and 0.27 ± 0.03 ng mL 1, respectively. Nine of 12 male-exposed hinds exhibited a preovulatory LH surge within 24 to 32 h postCIDR device withdrawal, whereas 0 of 6 male-isolated hinds exhibited a preovulatory LH surge during the same time period. Onset of behavioral estrus (45.2 ± 2.3, 52.7 ± 5.7 and 66.3 ±1.8 h, respectively) was significantly advanced (P < 0.05) after CIDR device withdrawal in male exposed hinds (Groups 1 and 2) compared with male isolated hinds (Group 3). These data suggest that stag exposure is important for modulating the timing of the preovulatory LH surge and behavioral estrus after synchronization of estrus with exogenous progestagens.

Successful in vitro fertilization of in vivo matured oocytes aspirated laparoscopically from red deer hinds ( [formula omitted

Most current protocols of in vitro fertilization in ruminants are based on in vitro maturation of oocytes derived from abattoir material. For application of IVF technology to captive endangered species, however, noninvasive techniques are required which allow repeated collection of oocytes from live females. The aim of this study was to develop a method for embryo production from mature oocytes collected laparoscopically from red deer hinds. Follicular development was synchronized in red deer hinds by the insertion of intravaginal progesterone-releasing devices for 10 d, and ovarian stimulation was induced with 1000 IU, im PMSG 48 h before progesterone device removal. Oocytes were harvested by laparoscopy under xylazine/ketamine sedation 24 h after progesterone device removal and then co-incubated with frozen-thawed red deer spermatozoa for 24 h. In Experiment 1, oocytes and embryos were fixed and stained at different developmental timepoints. Their external morphological changes (cumulus expansion, extrusion of the second polar body and cytokinesis) paralleled their nuclear developmental changes (formation of the 2nd metaphase spindle of meiosis, pronuclear formation and nuclear division, respectively). In Experiment 2, embryos were maintained in vitro until they ceased to undergo cell division. A total of 39 aspiration procedures was carried out on 14 red deer hinds. Forty-four cumulus-oocyte complexes (COC) were aspirated from 95 large Graafian follicles; of these, 27 were classed as mature/nondegenerated on the basis of cumulus/cytoplasmic morphology. Seventeen oocytes cleaved following in vitro fertilization, yielding six 2-cell embryos, six 4-cell embryos, four 8-cell embryos and one 16-cell embryo. The results indicate that laparoscopic aspiration of mature oocytes from hormone-treated females offers a valuable source of genetic material for assisted deer breeding programs.

Effects of mixed-species stocking and space allowance on the behaviour and growth of red deer hinds and ewes at pasture

Our objective was to test whether the effects of space allowance on social interactions, activity patterns and growth rates of hinds reared at pasture in single-species groups, were modified by mixing them with ewes. Thirty individuals of each species were assigned to two single-species groups of 10 animals (hinds: H1 and H2, ewes: E1 and E2) and to two mixed-species groups of 5 hinds and 5 ewes (M1 and M2). For 28 days, H1, E1 and M1 were kept at high space allowance (HSA: 267 m 2/animal) and H2, E2 and M2 at low space allowance (LSA: 67 m 2/animal) and for the following 28 days, the space allowance was reversed. Mean interindividual distances in single-species groups were lower at LSA than at HSA (hinds: 10.0±0.3 vs. 15.4±4.8 m, P<0.05; ewes: 7.9±0.5 vs. 11.0±2.5 m, NS). In mixed-species groups, distances between standing individuals of the same species were less than between individuals of a different species (hinds: 8.8±1.6 vs. 11.0±1.0 m, NS; ewes: 5.3±1.1 vs. 7.5±2.3 m, NS; hinds-ewes: 14.6±0.9 vs. 20.6±1.0, P<0.05, at LSA and HSA, respectively). Agonistic encounters between hinds were more frequent at LSA than at HSA when reared in single-species groups (median number of agonistic interactions/hour: 10.0 (9.6–12.8) vs. 5.0 (1.9–11.6), P<0.05). When reared in single-species groups, hinds were less synchronised during grazing at LSA than at HSA and they had shorter and more frequent meals. Such effects were not observed for ewes. Rearing the animals in mixed-species groups increased the effects of a restricted space allowance on grazing meals of hinds with a tendency to increase the number of meals and to reduce meal duration. In mixed-species groups, the effect of space allowance on ewes was more marked than when in single-species groups with ewes eating shorter and more frequent meals. The hinds reared in single-species groups grew slower at LSA than at HSA (185±63 vs. 225±42 g/day, P<0.01), whereas ewes grew at the same rates regardless of space allowance (175±53 vs. 185±54 g/day, at LSA and HSA, respectively, NS). In mixed-species groups, growth of both hinds and ewes was lower when space was restricted (hinds: 141±42 vs. 211±56 g/day, ewes: 170±47 vs. 202±32 g/day, at LSA and HSA, respectively, all P<0.05). In conclusion, restricting the space allowance resulted in behavioural changes and lower performance which were intensified by mixed-species stocking.

Lactation curves in captive Iberian red deer (Cervus elaphus hispanicus).

This study examines milk production and the effect of milk production and sex of calf on body weights and gains of red deer calves and hinds of the Iberian subspecies (Cervus elaphus hispanicus). Milk production was assessed in 14 hinds by weighing calves before and after suckling and by adjusting these values to the Gamma function. Gamma estimates of total milk production up to d 105 were similar to the amounts computed directly from double weighing. Hinds showed two types of lactation curve: 1) the standard mammal lactation curve, with an asymmetrical peak at wk 2 to 4 (Type I) and 2) decreasing curves with no peak (Type II). Although there was great interindividual variability, hinds with Type I curves showed a trend to produce more milk than those with Type II. The type of curve did not seem to affect weight variables of the calf or those of the dam. Calves that gained more weight consumed greater amounts of milk (P<.05). Males were heavier than females at birth (P<.05), but males did not differ from females in their weight at 105 d, milk consumption, and gain. Gender did not affect hind weight, but dams of male calves showed a trend to be lighter (P = .063) at d 105 than dams of female calves. Our results suggest that suckling differences found in other studies between male and female calves may not involve differences in milk production, although other rearing costs seem to affect hind weight losses. They also suggest that the curve type may not depend only, as reported, on the nutrition plane.

Brief communication. Hybridization between sika deer (Cervus nippon) and axis deer (Axis axis)

We report an incidence of hybridization from natural mating between sika deer (Cervus nippon) and axis deer (Axis axis). A female exhibiting physical characteristics intermediate between the two species was born on a Tennessee deer farm sometime in 1995. Gel electrophoresis of three blood proteins (TF, HBB, and SOD) from the putative hybrid, the putative sika deer sire and three axis deer hinds from the herd (not necessarily including the dam) initially verified that hybridization had occurred. Q-banded karyotypes further identified the offspring as a hybrid (2n = 67) between sika deer (2n = 68) and axis deer (2n = 66). Fertility of the hybrid remains to be assessed, although it is now of reproductive age.

Involvement of serotoninergic pathways in the control of luteinizing hormone secretion in red deer hinds.

Two experiments were conducted to determine whether serotoninergic pathways, which are implicated in the neuroendocrine regulation of luteininzing hormone (LH) secretion in domestic animals, have a similar action in red deer hinds. In the non-breeding season (August), ovariectomized (n = 5) and ovariectomized-thyroidectomized (n = 5) hinds received a vehicle solution followed 4 h later by either serotonin (66 microg kg(-1) i.v.) every 10 min for a further 4 h or the serotonin antagonist, cyproheptadine (3 mg kg(-1) i.v.) as a single injection. This procedure was repeated in the breeding season (June). In the non-breeding season serotonin was without effect, but cyproheptadine reduced LH pulse frequency and amplitude in ovariectomized-thyroidectomized hinds (P<0.01). During the breeding season, serotonin reduced LH pulse amplitude in ovariectomized hinds (P<0.05) and cyproheptadine reduced LH pulse frequency in both ovariectomized and ovariectomized-thyroidectomized hinds (P<0.05 and P<0.01, respectively). On each occasion, cyproheptadine increased (P<0.01) plasma prolactin concentration, whereas serotonin had no effect. These results indicate a stimulatory role for serotoninergic neurons on the hypothalamic GnRH pulse generator mechanism of red deer hinds during the breeding season. In a second experiment, the LH response to GnRH (5 microg i.v.) was examined in ovariectomized hinds (n = 5) following administration of a serotonin infusion (6.6 microg kg(-1) min(-1) i.v. for 15 min), cyproheptadine (3 mg kg(-1) i.v. as a single dose) or vehicle, in the breeding season (July) after induction of halothane anaesthesia and in the non-breeding season (December) without anaesthesia. Halothane anaesthesia eliminated endogenous pulses of LH. In comparison with the vehicle-treated controls, the response of plasma LH to exogenous GnRH was not altered by serotonin or cyproheptadine in either season, which shows that serotonin has no effect on LH release at the pituitary gland level in these animals. It was concluded that in the regulation of LH release in red deer hinds, serotoninergic pathways have a stimulatory role operating at the hypothalamic level.