Gazella Dama Research Articles

Mother traits and offspring sex in two threatened gazelle species in captivity

Since threatened species are generally incapable of surviving in their natural environments, ex situ conservation programs are required to preserve them from total extinction. Captive breeding provides the tool to rear sustained populations. Knowledge about biology of such species is critical for managing such breeding programmes. In this paper, we look at the sex variation in calves surviving to 30 days in captive populations of two endangered polygynous gazelles, Gazella cuvieri and Gazella dama mhorr. We examined which of the following mother traits may affect sex allocation: her age; experience; and inbreeding coefficient. Because twins are quite common in Cuvier's gazelle, we also analyse whether offspring sex is mediated by litter size in this gazelle. In both species the overall sex ratio did not differ from unity at the age of 30 days. These results support the suggestion that for a given population to be in equilibrium, a 1:1 calf sex ratio is to be expected, with females in good condition producing sons and females in poor condition producing daughters. We also found that offspring sex is not significantly related to the same mother traits in the two gazelles studied. Cuvier's gazelle findings showed that only maternal inbreeding influenced offspring sex, the less inbred the mother the higher the probability of producing sons. In contrast, none of the maternal traits studied were related to offspring sex in Mohor gazelle. Two nonexclusive explanations are given to justify differences observed between these two species; one relates to a probable differential cost of producing either sex; the other refers to the actual homozygosis level in captive populations of each species. For Cuvier's gazelle litter size has no effect on offspring sex when the sex of the littermate is taken into account. This result fits predictions derived from Trivers–Willard model: mother in good conditions (less inbred) produce the sex with higher fitness returns (i.e., male), no matter if born at single or twins brood. Many variables are likely to affect progeny sex ratio. We have presently examined only a few. But our results might be of interest in management decisions and conservation programs such as reintroductions.

Serum concentrations of insulin‐like growth factor‐i and insulin‐like growth factor binding protein‐2 and ‐3 in eight hoofstock species

The somatotropic axis, which includes growth hormone, insulin-like growth factor (IGF)-I, and IGF binding proteins (IGFBP), is involved in the regulation of growth and metabolism. Measures of the somatotropic axis can be predictive of nutritional status and growth rate that can be utilized to identify nutritional status of individual animals. Before the somatotropic axis can be a predictive tool, concentrations of hormones of the somatotropic axis need to be established in healthy individuals. To begin to establish these data, we quantified IGF-I, IGFBP-2, and IGFBP-3 in males and females of eight threatened hoofstock species at various ages. Opportunistic blood samples were collected from Bos javanicus (Java banteng), Tragelaphus eurycerus isaaci (bongo), Gazella dama ruficollis (addra gazelle), Taurotragus derbianus gigas (giant eland), Kobus megaceros (Nile lechwe), Hippotragus equines cottoni (roan antelope), Ceratotherium simum simum (white rhinoceros), and Elephas maximus (Asian elephant). Serum IGF-I and IGFBPs were determined by radioimmunoassay and ligand blot, respectively. Generally, IGF-I and IGFBP-3 were greater in males, and IGFBP-2 was greater in females. In banteng (P = 0.08) and male Nile lechwe (P < 0.05), IGF-I increased with age, but decreased in rhinoceros (P = 0.07) and female Nile lechwe (P < 0.05). In banteng, IGFBP-3 was greater (P < 0.01) in males. In elephants (P < 0.05) and antelope (P = 0.08), IGFBP-2 were greater in females. Determination of concentrations of hormones in the somatotropic axis in healthy animals makes it possible to develop models that can identify the nutritional status of these threatened hoofstock species.

Effects of fecal age and seasonality on steroid hormone concentration as a reproductive parameter in field studies

We studied how fecal age (6, 12, 24, 48, 72, and 168 h) and seasonality affect variation in the fecal steroid hormone metabolite concentration in three endangered mammalian species, Mhorr gazelle, Saharan Barbary sheep, and the Iberian lynx. Except for estrogens, concentrations remained stable for at least 48 h in the Mhorr gazelle and the Saharan Barbary sheep. Steroid hormone metabolite concentration remained stable in the Iberian lynx throughout the experiment (1 week). Seasonality was the main factor affecting variation in hormone metabolite concentrations, and although the response was species- and hormone-specific, the dry season resulted in increased hormone metabolite concentrations, while the wet season reduced the concentration.

Coxiella burnetii Abortion in Captive Dama Gazelle (Gazella dama) in the United Arab Emirates

Abstract: Five cases of late-stage abortion in dama gazelle (Gazella dama) occurred in the United Arab Emirates. Histopathologic and molecular diagnostics found the abortions to be associated with Coxiella burnetii infection. Examination of the herd 6 mo later revealed a significant number of serologically positive animals but failed to detect the antigen in genital swabs. There are few reports in the literature of C. burnetii abortion in nondomestic ungulates and no published reports from the United Arab Emirates.

Use of a neuroleptic in assisted reproduction of the critically endangered Mohor gazelle ( Gazella dama mhorr)

Stress is a limiting factor in assisted reproduction in wild animals maintained in captivity and measures to reduce it should improve reproductive success. The effect of the long-acting neuroleptic (LAN) perphenazine enanthate was assessed on ovarian stimulation for the recovery of immature oocytes from Mohor gazelle ( Gazella dama mhorr) and their subsequent in vitro maturation, fertilization and embryo culture. The viability of embryos after transfer was also examined. Perphenazine enanthate decreased activity levels and facilitated handling of treated animals when compared to controls. LAN-treated animals showed a more regular pattern of respiratory and heart rates and body temperature than controls; no major differences were found in hematological and biochemical parameters between groups. Perphenazine-treated females had lower plasma cortisol levels during the days of intense handling. No significant differences were found in the number of punctured follicles and recovered oocytes between groups. The percentage of mature oocytes per female was significantly higher in the LAN-group. Fertilization and cleavage rates were not significantly different between groups. Embryos developed in culture but none reached the blastocyst stage, and those transferred to the oviduct of synchronized recipients did not develop to term. In conclusion, treatment of females with perphenazine enanthate during ovarian stimulation did not have negative effects on maturation, fertilization and embryo development in vitro. Moreover, an increase in oocyte maturation rate per female was observed. Thus, the use of LANs could be useful to alleviate the effects of handling-stress during assisted reproductive procedures in wild ungulates.

In vitro oocyte maturation, fertilization and culture after ovum pick-up in an endangered gazelle (Gazella dama mhorr)

The recovery of immature oocytes followed by in vitro maturation, fertilization and culture (IVMFC) allows the rescue of biological material of great genetic value for the establishment of genetic resource banks of endangered species. Studies exist on sperm cryopreservation of endangered Mohor gazelle (Gazella dama mhorr), but no work has been carried out yet on oocyte collection, fertilization and culture in this or related species. The purpose of this study was to develop a protocol for ovarian stimulation for the recovery of oocytes and subsequent IVMFC in the Mohor gazelle using frozen-thawed spermatozoa. Ovum pick-up was performed after ovarian stimulation with a total dose of 5.28 mg of ovine FSH. A total of 35 oocytes were recovered from 56 punctured follicles (62%) (N=6 females). Out of 29 cumulus-oocyte complexes matured in vitro, 3% were found at germinal vesicle stage, 7% at metaphase I, 21% were degenerated, and 69% advanced to metaphase II. Fertilization and cleavage rates of matured oocytes were 40 and 30%, respectively. Embryos cleaved in vitro up to the 6-8 cell stage but none progressed to the blastocyst stage, suggesting the existence of a developmental block and the need to improve culture conditions. Although more studies are needed to improve hormonal stimulation and oocyte harvesting, as well as IVMFC conditions, this study demonstrates for the first time the feasibility of in vitro fertilization with frozen-thawed semen of in vitro matured oocytes collected by ovum pick-up from FSH-stimulated endangered gazelles.

Confirmation of the survival of the Critically Endangered dama gazelle Gazella dama in south Tamesna, Mali

In February 2005 a survey confirmed the existence of Critically Endangered dama gazelle Gazella dama in south Tamesna, eastern Mali. Two zones, covering an area of 1,775 km2, were systematically surveyed. Seven gazelles were seen and evidence was found of 18 additional individuals, giving an estimated density of 0.047 gazelles km−2. The dama gazelles are taking refuge in places where it is difficult to drive because of a strongly-marked relief and the presence of grassy tussocks. Preliminary genetic analysis of faeces indicates that these gazelles belong to the subspecies Gazella dama dama. These populations are of particular importance for the conservation of the dama gazelle, and an aerial survey has been planned to confirm the terrestrial observations. The government of Mali has, however, already decided to create three protected areas in Tamesna for the conservation of the dama gazelle and Vulnerable dorcas gazelle Gazella dorcas.

Inbreeding and Reproduction in Endangered Ungulates: Preservation of Genetic Variation through the Organization of Genetic Resource Banks

There is a constant increase in the number of species suffering marked reductions in population size. This reduction in size and the lack of genetic flow may lead to a decrease in genetic variability and to matings between close relatives (i.e. inbreeding) with an ensuing reduction in fitness. It is thus important to understand the mechanism underlying the deleterious effects of inbreeding and to develop reproductive biotechnologies that will allow the reduction of inbreeding depression by facilitating gene exchange between populations. The study of three endangered species of gazelles, Cuvier's gazelle (Gazella cuvieri), Mohor gazelle (Gazella dama mhorr) and dorcas gazelle (Gazella dorcas neglecta) has revealed that inbreeding negatively affects several semen parameters (motility, sperm morphology, acrosome integrity). Semen cryopreservation has been achieved in the three species but success varies depending on the diluent employed and the level of inbreeding. Artificial insemination of Mohor gazelles have led to the birth of the first gazelle born using frozen-thawed semen but improvements are needed before this technology can be applied on a routine basis for the genetic management of the populations. Collection of oocytes after ovarian stimulation, followed by in vitro maturation, fertilization and culture has met with some initial success in the Mohor gazelle. These, together with other reproductive technologies, will offer an invaluable help in preserving the maximum of genetic diversity of these and related endangered ungulate species.

OUTPUT OF GASTROINTESTINAL NEMATODE EGGS IN THE FECES OF CAPTIVE GAZELLES (GAZELLA DAMA MHORR, GAZELLA CUVIERI AND GAZELLA DORCAS NEGLECTA) IN A SEMIARID REGION OF SOUTHEASTERN SPAIN

Feces from 62 captive African gazelles, including Mhorr gazelles (Gazella dama mhorr), Cuvier's gazelles (Gazella cuvieri), and Dorcas gazelles (Gazella dorcas neglecta), were examined over the course of a year to quantitate nematode egg excretion patterns. Strongyloides sp. eggs appeared only in G. dama during the rainy season. Trichostrongylidae egg excretion showed a marked seasonal variation, with very low levels during the dry and hot period, a finding that is probably attributable to hypobiosis of the predominant species (Camelostrongylus mentulatus). Eggs of the Nematodirus sp., predominantly Nematodirus spathiger, were excreted throughout the year. No seasonal pattern was observed in Trichuris sp. egg excretion.

SERUM GAMMA-GLUTAMYLTRANSFERASE AS A PROGNOSTIC INDICATOR OF NEONATAL VIABILITY IN NONDOMESTIC RUMINANTS

Rapid assessment of immune status in neonatal ruminants of endangered species facilitates early intervention in cases of inadequate passive transfer of maternal immunoglobulins. Serum gamma-glutamyltransferase (GGT) was used to evaluate suspected passive transfer status in 25 North Indian muntjac (Muntiacus muntjak vaginalis), 45 Cretan goats (Capra algagrus cretica), 20 white-lipped deer (Cervus albirostris), 25 Mhorr gazelles (Gazella dama mhorr), and 31 Soemmerring's gazelles (Gazella soemmerringi soemmerringi). Serum GGT, measured within 48 hr of birth, was compared with clinical condition at 5 days of age. Neonatal Soemmerring's and Mhorr gazelles with GGT > 600 U/L were likely to survive without medical intervention, whereas GGT < 400 U/L was a good indicator that the gazelle neonate would need medical intervention. Neonatal muntjac with GGT > 200 U/L were also likely to survive without medical intervention. Because there is no gold standard for evaluating passive transfer status in neonatal nondomestic ruminants, it is recommended to evaluate the results of more than one diagnostic test, as well as clinical condition, in considering health status and disposition of neonatal ruminants of endangered species.

TRANSPOSITION OF THE BICEPS TENDON TO REDUCE LATERAL SCAPULOHUMERAL LUXATION IN THREE SPECIES OF NONDOMESTIC RUMINANT

Open reduction of lateral luxation of the scapulohumeral joint was performed in a Mhorr gazelle (Gazella dama mhorr), a southern pudu (Pudu puda), and an Alpine ibex (Capra ibex ibex) by transposition of the biceps brachii tendon lateral to the greater tubercle of the humerus. The ibex had a very large greater tubercle that required a second osteotomy to allow successful lateral transfer of the tendon. Although all three animals were non-weight bearing in the first 2-3 wk after surgery, ambulation improved at 3 wk and was almost normal by 6 wk after surgery. Postoperative follow-up of 8 yr, 7 mo, and 3 mo in the gazelle, pudu, and ibex, respectively, revealed normal ambulation with no gait deficits. The gazelle was euthanized 8 yr after surgery for unrelated disease and necropsy demonstrated mild to moderate degenerative joint disease. Similar lateral shoulder luxations in comparably sized, nondomestic ruminants, without concurrent fractures or significant joint abnormality, have a good prognosis for return to function after surgical reduction using a biceps tendon transposition.

220 LIVE BIRTH OF A MOHOR GAZELLE (GAZELLA DAMA MHORR) CALF FOLLOWING INTRAUTERINE INSEMINATION OF MOTHER WITH FROZEN - THAWED SEMEN

Gazella dama mhorr is an endangered species, and no animals have been observed in the wild since 1968. Assisted reproductive techniques have been used to propagate endangered species. However, no live offspring has been produced after cryopreservation of semen from gazelle species. Therefore, the objective of this study was to evaluate whether cryopreserved Mohor gazelle spermatozoa can fertilize in vivo after artificial insemination. Semen was collected by electroejaculation from four males and centrifuged at 700g for 5 min at room temperature. The supernatant was discarded, and the semen pellet was resuspended with a TEST-1% egg yolk diluent containing 6% glycerol to provide 400 � 106 spermatozoa/mL. The extended semen was loaded into 0.25-mL plastic straws, cooled slowly to 5�C, and equilibrated at 5�C for 2 h. Straws were frozen in nitrogen vapors for 10 min and then plunged into liquid nitrogen. After thawing (37�C, 30 s), the effects of cryopreservation on sperm motility and acrosomal integrity were examined. Percentage of motile sperm in fresh samples was 88.7 � 3.8% (mean � SEM), decreased (P &lt; 0.0001) to 58.7 � 3.8% after freezing and thawing, and then to 40.0 � 3.8% after 120 min incubation at 37�C. Spermatozoa with normal acrosomes decreased (P &lt; 0.0001) after freezing and thawing (from 94.5 � 4.2% to 56.0 � 4.2%), but did not significantly decrease after sperm incubation. Frozen spermatozoa from two males were used in an intrauterine insemination trial. Estrus of females (n = 15) was synchronized with controlled internal drug release (CIDR, InterAg, Hamilton, New Zealand). Single CIDRs (type G, 330 mg progesterone/device) were inserted intravaginally for a total of 13 days. On Day 10, devices were replaced in each animal and all females received an injection of prostaglandin F2� (PGF2�; 125 mg/female). At CIDR withdrawal, females received 250-300 IU equine chorionic gonadotropin (eCG: Folligon; Intervet, Salamanca, Spain). After anesthesia with an intravenous injection of xylazine hydrochloride (Rompun; Bayer, Madrid, Spain; 0.8 mg/kg live weight) and ketamine hydrochloride (Imalgene; Leti &amp; Merieux, Madrid, Spain; 2.0 mg/kg live weight), eight females were inseminated with 100 � 106 frozen-thawed spermatozoa 56-57 h after removal of the CIDRs, and seven were inseminated after 64-65 h. Females were inseminated directly into the uterus using laparoscopy. Anesthesia was reversed with yohimbine hydrochloride (0.3 mg/kg live weight). One female in the second group became pregnant. After a 202-day gestation, the female gave birth to one healthy Mohor gazelle male calf. These results demonstrate for the first time the successful use of frozen-thawed semen by means of artificial insemination for the rescue of endangered gazelle species. However, our results reveal that a number of unresolved technical problems remain to be addressed. This work was supported by the Spanish Ministry of Education and Science (REN2003-1587).

216 IN VITRO OOCYTE MATURATION, FERTILIZATION, AND CULTURE AFTER LAPAROSCOPIC OVUM PICK-UP IN AN ENDANGERED GAZELLE (GAZELLA DAMA MHORR)

The recovery of immature oocytes followed by in vitro maturation, fertilization and culture (IVMFC) allows the rescue of biological material of great genetic value for the establishment of genetic resource banks. Studies have been carried out on endangered Mohor gazelle sperm cryopreservation (Garde et al. 2003 Biol. Reprod. 69, 602-611), but there are no studies on oocytes in this species. The purpose of this work was to develop a protocol for ovarian stimulation for the recovery of oocytes and subsequent IVMFC. The study was conducted using six reproductively mature female Mohor gazelles from the breeding herd at the Estacion Experimental de Zonas Aridas. Animals were synchronized by insertion of controlled progesterone internal drug release (CIDR) devices for 14 days and removal of the devices on the day of ovum pickup (OPU). Follicular growth was stimulated by a total of 5.28 mg of oFSH (Ovagen, ICP, Auckland, New Zealand) given in four equal doses every 12 h. OPUs were performed (Berlinguer et al. 2004 Theriogenology 61, 1477-1486) on Day 15 from the beginning of treatment, and follicles were aspirated with a syringe and a 25G needle using TCM199-HEPES with 50 �g/mL streptomycin, 50 IU/mL penicillin, 0.1% polyvinyl alcohol, and 15 IU/mL heparin. Degenerated oocytes and those with expanded cumulus were removed. Oocytes were cultured in TCM-199 plus 10% FCS, 10 �g/mL ovine FSH/LH, 1 �g/mL estradiol, and 0.1 mg/mL glutamine at 38.5�C under 5% CO2/air and maximum humidity. Spermatozoa were cryopreserved in Tes-Tris with 5% egg yolk and 6% glycerol, and selected by swim-up in SOF medium. After 24 h sperm-oocyte coincubation (sperm concentration: 1 � 106/mL) in SOF with 2% estrus sheep serum under 5% CO2 5% O2 90% N2, presumptive zygotes were transferred to SOF with 0.4% BSA and amino acids under 5% CO2, 5% O2 90% N2 and cultured for 4 days. Oocytes and embryos were stained with Hoechst 33342 and propidium iodide (1 �g/mL each) and visualized under a fluorescence microscope. A total of 35 oocytes were recovered from 56 punctured follicles (62.5%). This recovery rate was similar to those in wildlife in earlier reports, but more studies are needed to improve hormonal stimulation and oocyte harvesting. Out of 29 cumulus-oocyte complexes matured in vitro, 3.5% were found at GV and 6.9% at MI; 20.7% were degenerated and 68.9% had advanced to MII. Fertilization and cleavage rates were 40% and 30%, respectively, of matured oocytes. Out of eight zygotes, six showed cleavage (ranging from 2 to 8 cells). None of the developing embryos progressed to the blastocyst stage, suggesting the existence of a developmental block and the need to improve culture conditions. Although more trials will help to improve IVMFC, this study demonstrates for the first time the feasibility of in vitro fertilization with frozen-thawed semen of in vitro matured oocytes collected by OPU from FSH-stimulated endangered gazelles. This work was supported by the Spanish Ministry of Education and Science (REN 2003-11587) and Acciones Integradas (HI20030336).

Inbreeding depression on reproductive performance and survival in captive gazelles of great conservation value

Here I present a detailed analysis of individual inbreeding coefficient effects on some reproductive parameters and longevity in three species of gazelles under different conservation status: vulnerable dorcas gazelle, endangered Cuvier’s gazelle, and extinct in the wild mhorr gazelle. The novelty of this study stems from the inclusion of both males and females in analyses including a large database of information collected during two decades of periodical studbook inventories for these species. Translocations to different zoo locations of the extinct subspecies mhorr gazelle do not apparently affect reproductive performance (population sex ratio) or individual longevity. In agreement with previous works, the average inbreeding coefficients vary inter-specifically, being higher in Cuvier’s, followed by mhorr and dorcas gazelles. This reflects the different population size of the founding individuals of each species’ captive population. Sexual maturity and age at first birth follow an allometric pattern, occurring at an earlier age in the smallest species (dorcas), followed by Cuvier’s and then the mhorr gazelle. Twinning in Cuvier’s gazelle depends on maternal experience, as it is less frequent in primiparous females. Inbreeding affects neither twinning nor sex ratio. Mhorr gazelles’ studbook shows several causes of death and it emerges that a higher proportion of non-inbred females die due to pathologies than males, although both sexes show similar proportion of mortal pathologies when inbred. Multifactor ANOVA shows that longevity decreases with inbreeding level and that females live longer than males in the three species of gazelles studied, as expected in polygynous mammals. Mhorr and dorcas non-inbred females show higher juvenile survival than males, whereas inbred individuals show a similar declining juvenile survival, particularly in mhorr and Cuvier’s gazelles. Finally, it is discussed the apparent inbreeding tolerance in Cuvier’s species, and the great value keeping and studying long term data of well-monitored captive populations may prove to the conservation of threatened species.

Periparturient increase in faecal egg counts in a captive population of mohor gazelle (Gazella dama mhorr)

The objective of this study was to assess whether there was a periparturient rise in the faecal egg output of a population of North African gazelles (Gazeia dama mhorr) kept...

Endocrine correlates of sexual behavior in the Mohor gazelle ( Gazella dama mhorr)

In this study, we quantitatively examined male sexual behavior in relation to fecal estrogen and progesterone concentrations in female Mohor gazelles. We investigated the hypothesis that, during natural mating, males detect cues relating to the potential for successful conception and pregnancy. Time series analysis revealed that males could detect the approach of estrus 2–3 days before female fecal estrogens and estrogen/progestagen (E/P) ratio reached their peak values. Males also paid closer attention to those females excreting higher fecal estrogen concentrations. Mounting and copulation frequencies were positively correlated with both peri-ovulatory fecal estrogen concentrations, and the frequency of pre-copulatory courtship behaviors. These data suggested that males invest their reproductive effort selectively by mating the most fertile females, assuming that estrogen is a valid index of fertility. This assumption was investigated by examining sequential phases of the reproductive cycle for evidence that oocytes and follicles produced in a more estrogenic environment would lead to the formation of the most competent corpora lutea, thereby maximizing the chance of sustaining pregnancy. Associations between sexual behavior and hormone excretion support the hypothesis that males may use this mechanism to assess female fertility.

Hormonal characterization of the reproductive cycle and pregnancy in the female Mohor gazelle (Gazella dama mhorr).

The oestrous cycles of seven captive Mohor Gazelles (Gazella dama mhorr) were investigated. Hormone profiles obtained from faecal samples collected each day from cyclic females indicated that the mean duration of the oestrous cycle was 18.62 +/- 0.26 days (range 16-22 days; n = 37 oestrous cycles). No inter-individual differences in the concentration of faecal progestagen metabolites excreted were observed, but mean faecal oestrogen excretion during both the luteal and inter-luteal phases of the oestrous cycle varied among females (P < 0.001 and P = 0.070, respectively). Oestrous cycles were synchronized using controlled internal drug release (CIDR) devices, before natural mating with an intact male. Concentrations of faecal progestagen metabolites remained approximately constant for the first 10 weeks of gestation (mean +/- SEM = 4048 +/- 407 ng g(-1) faeces), before increasing to a mean of 23 556 +/- 1176 ng g(-1) faeces. Two of seven female gazelles conceived immediately after removal of the CIDR device, a similar proportion to that conceived at the postpartum oestrus under natural conditions. Life history data for these individuals indicated that the mean time to conception in female gazelles is positively correlated with peak values in the ratio of excreted oestrogen : progestagen during the inter-luteal period of their oestrous cycles (R(2) = 0.58; P < 0.05). This finding indicates that interactions between steroid production and metabolism may influence the likelihood of conception occurring in this species.

Hormonal characterization of the reproductive cycle and pregnancy in the female Mohor gazelle (Gazella dama mhorr)

The oestrous cycles of seven captive Mohor Gazelles (Gazella dama mhorr) were investigated. Hormone profiles obtained from faecal samples collected each day from cyclic females indicated that the mean duration of the oestrous cycle was 18.62 +/- 0.26 days (range 16-22 days; n = 37 oestrous cycles). No inter-individual differences in the concentration of faecal progestagen metabolites excreted were observed, but mean faecal oestrogen excretion during both the luteal and inter-luteal phases of the oestrous cycle varied among females (P < 0.001 and P = 0.070, respectively). Oestrous cycles were synchronized using controlled internal drug release (CIDR) devices, before natural mating with an intact male. Concentrations of faecal progestagen metabolites remained approximately constant for the first 10 weeks of gestation (mean +/- SEM = 4048 +/- 407 ng g(-1) faeces), before increasing to a mean of 23 556 +/- 1176 ng g(-1) faeces. Two of seven female gazelles conceived immediately after removal of the CIDR device, a similar proportion to that conceived at the postpartum oestrus under natural conditions. Life history data for these individuals indicated that the mean time to conception in female gazelles is positively correlated with peak values in the ratio of excreted oestrogen : progestagen during the inter-luteal period of their oestrous cycles (R(2) = 0.58; P < 0.05). This finding indicates that interactions between steroid production and metabolism may influence the likelihood of conception occurring in this species.

Use of computer-assisted sperm motility assessment and multivariate pattern analysis to characterize ejaculate quality in Mohor gazelles (Gazella dama mhorr): effects of body weight, electroejaculation technique and short-term semen storage.

Subjective and objective semen assessments were performed on 18 male Mohor gazelles (Gazella dama mhorr). Sperm motility assessments combined with sperm plasma membrane and acrosomal integrity evaluations were undertaken as part of a captive breeding programme. The primary objective was to test methodology for short-term preservation of gazelle semen for artificial insemination (storage in N-[Tris(hydroxymethyl)methyl]-2-aminoethanesulphonic acid-Tris diluent (TEST) for up to 96 h at 17 degrees C). However, the secondary objective was to investigate phenotypic and genotypic influences on semen quality within this small population, which was established in 1971 with only 12 genetic founders. Sperm motility was measured by computer-assisted semen assessment and the data were analysed using a pattern analysis technique to detect and quantify naturally occurring sperm subpopulations within the semen samples. Four sperm subpopulations distinguishable by their motion characteristics were detected. The relative frequencies of two subpopulations (population 2: highly motile, non-linear; and population 4: poorly motile, non-linear) in fresh semen were correlated with the maximum voltage used during electroejaculation. The frequency of subpopulation 2 was negatively correlated with maximum voltage (r = -0.875, P < 0.0001) and the frequency of subpopulation 4 was positively correlated (r = 0.727, P < 0.005). The frequencies of all subpopulations varied significantly among the animals sampled (chi-squared = 2577.6, degrees of freedom = 54, P < 0.0001) and subpopulation 4 was also correlated with body weight (r = -0.59, P < 0.005). Semen stored at 17 degrees C retained motility, plasma membrane and acrosomal integrity for 48 h, but these measures decreased thereafter. The frequency of a sperm subpopulation showing uncoordinated but active motility increased significantly over the first 48 h and then decreased.

Use of computer-assisted sperm motility assessment and multivariate pattern analysis to characterize ejaculate quality in Mohor gazelles (Gazella dama mhorr): effects of body weight, electroejaculation technique and short-term semen storage

Subjective and objective semen assessments were performed on 18 male Mohor gazelles (Gazella dama mhorr). Sperm motility assessments combined with sperm plasma membrane and acrosomal integrity evaluations were undertaken as part of a captive breeding programme. The primary objective was to test methodology for short-term preservation of gazelle semen for artificial insemination (storage in N-[Tris(hydroxymethyl)methyl]-2-aminoethanesulphonic acid-Tris diluent (TEST) for up to 96 h at 17 degrees C). However, the secondary objective was to investigate phenotypic and genotypic influences on semen quality within this small population, which was established in 1971 with only 12 genetic founders. Sperm motility was measured by computer-assisted semen assessment and the data were analysed using a pattern analysis technique to detect and quantify naturally occurring sperm subpopulations within the semen samples. Four sperm subpopulations distinguishable by their motion characteristics were detected. The relative frequencies of two subpopulations (population 2: highly motile, non-linear; and population 4: poorly motile, non-linear) in fresh semen were correlated with the maximum voltage used during electroejaculation. The frequency of subpopulation 2 was negatively correlated with maximum voltage (r = -0.875, P < 0.0001) and the frequency of subpopulation 4 was positively correlated (r = 0.727, P < 0.005). The frequencies of all subpopulations varied significantly among the animals sampled (chi-squared = 2577.6, degrees of freedom = 54, P < 0.0001) and subpopulation 4 was also correlated with body weight (r = -0.59, P < 0.005). Semen stored at 17 degrees C retained motility, plasma membrane and acrosomal integrity for 48 h, but these measures decreased thereafter. The frequency of a sperm subpopulation showing uncoordinated but active motility increased significantly over the first 48 h and then decreased.