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 (Gazella dama mhorr) kept in captivity in Almeria, southern Spain. In one experiment faeces were collected from 47 female gazelles on three days in winter, in November and December 1995 and January 1996; in a second experiment faecal samples were collected from nine pregnant gazelles at weekly intervals from July 1996 to June 1997. The mean trichostrongylid faecal egg counts were significantly higher (P < 0.05) in the periparturient gazelles than in the pregnant and non-pregnant animals only when the births took place in winter. Other factors, including the gazelle's age, its level of inbreeding, the number of previous births, and its trichostrongylid egg output at the beginning of the study did not affect whether it showed a periparturient rise. The parasites responsible for the rise were different in the two experiments.

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.

Effect of different methods of administration of ivermectin on its efficacy against the shedding of gastrointestinal nematode eggs by gazelles.

Seven different methods of administering ivermectin to gazelles were compared: subcutaneous injection, direct oral administration, administration in individual feeds, administration in a herd feed, direct oral administration of a second ivermectin formulation, administration in individual water supplies, and administration in the herd's water supply. The first five treatments were effective, as monitored by faecal egg count reduction tests, and administration in individual feeds or in a herd feed avoided the need to capture the animals, with the attendant risk of mortality. Of the factors associated with the recipients (species, sex, age and inbreeding coefficient) age was the only significant factor for the efficacy of the treatment. Oral or subcutaneous, individual or collective, and direct or indirect administrations were equally satisfactory for the treatment of all the parasite groups studied. Only when parasitic problems were due to Nematodirus species did direct administration to individual animals appear to be preferable.

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.

Oral administration of mebendazole failed to reduce nematode egg shedding in captive African gazelles.

Idiosyncracies are observed in captive wild animals as regards the pharmacokinetics and efficacy of anthelmintics. This could be attributed to such factors as differences in host's metabolism, irregular distribution of anthelmintics due to the way they are administered and worm resistance to anthelmintics. Previously mebendazole was found to be poorly effective when administered in feed. An experiment was conducted to evaluate the efficacy of mebendazole when administered at the dosage rate of 15-20 mg/kg body weight to gastrointestinal nematodes in captive gazelles. Fifty-eight adult gazelles (Gazella cuvieri) were divided into four groups: T1 (animals dosed orally, directly into the mouth), T2 (treated orally, mixed in the water of a herd), T3 (treated orally, mixed in the water of one animal), and T4 (not treated). Individual faecal samples were taken before treatment, and 15 days thereafter. Mean percentages of reduction of egg shedding were calculated for Nematodirus spp., other trichostrongyles, total trichostrongylids, Trichuris spp. and total nematodes. No statistically significant differences were detected between the treatment groups and the control group or among the animals in the three treatment groups.

Abomasal and small intestinal nematodes from captive gazelles in Spain.

The abomasal and small intestinal helminth fauna of three species of captive gazelles (Gazella dama mhorr, G. cuvieri and G. dorcas neglecta) kept in captivity in Almería (southeast Spain) have been studied, and the following species were identified: Nematodirus spathiger, N. filicollis, N. helvetianus, Camelostrongylus mentulatus, Trichostrongylus vitrinus, T. probolurus, T. colubriformis, Ostertagia ostertagi, O. harrisi, Teladorsagia (Ostertagia) circumcincta, and T. (Ostertagia) davtiani. Camelostrongylus mentulatus and N. spathiger were the most prevalent and abundant parasites. Ostertagia ostertagi, O. harrisi, N. helvetianus, and T. (Ostertagia) davtiani were identified for the first time in the genus Gazella. In addition, O. harrisi and Trichostrongylus probolurus are new records for Spain.

Sperm subpopulations in boar (Sus scrofa) and gazelle (Gazella dama mhorr) semen as revealed by pattern analysis of computer-assisted motility assessments.

The aim of this study was to test the suitability of "pattern analysis" for the exploration of data provided by computer-assisted semen analysis methods. Data sets derived from the examination of boar sperm responses to bicarbonate and caffeine (measurements on 3208 spermatozoa) and from studies of semen cryopreservation in Mohor gazelles (7278 spermatozoa) were reanalyzed. A nonhierarchical classification method was used to generate initial subgroups of spermatozoa (9 for boar, 13 for gazelle). The subgroup centroids were fused, yielding three boar sperm subpopulations and four gazelle sperm subpopulations distinguished by sperm behaviors. Bicarbonate and caffeine both induced major transitions (p < 0.0001) of boar sperm behavior, detected as shifts in group membership (from group 2, i.e., active but nonlinear movement, into group 1, i.e., linear, rapid movement). Some spermatozoa (approximately 3%) were refractory to both caffeine and bicarbonate. The gazelle sperm subpopulation structure was affected by the inclusion of equex (sodium triethanolamine lauryl sulfate) in the cryoprotective diluents. Equex suppressed the appearance of spermatozoa with erratic behavior (p < 0.0001; high curvilinear velocity, low linearity, low straight-line velocity) after cryopreservation. The proportion of these erratic spermatozoa was positively correlated with animal age (r = 0.68, p = 0.029). Pattern analysis revealed novel aspects of the data not seen in the original investigations and usefully supplemented the more standard data analysis approaches.

Characteristics of the semen of three endangered species of gazelles (Gazella dama mhorr, G. dorcas neglecta and G. cuvieri).

As part of a captive breeding programme for three species of endangered gazelles (Gazella dama mhorr, G. dorcas neglecta and G. cuvieri) the semen parameters for each species were characterized. The volume of ejaculated semen varied widely within species (G. dama: 565-5569 microliters; G. dorcas: 0-1454 microliters; G. cuvieri: 50-1411 microliters), as did sperm concentration (G. dama: 14-1629 x 10(6) ml-1; G. dorcas: 197-2836 x 10(6) ml-1; G. cuvieri: 228-927 x 10(6) ml-1). Sperm motility and viability were high in the three species. G. dama had a significantly lower proportion of normal spermatozoa, with a significantly higher proportion having abnormal heads and midpieces and more spermatozoa with cytoplasmic droplets. In addition, G. dama tended to have a lower proportion of spermatozoa with normal acrosomes. Sperm heads in G. dama and G. cuvieri were pear-shaped, whereas they were oval in G. dorcas. Spermatozoa from G. cuvieri were the longest. These data were also analysed in the context of three hypotheses that could explain inter-species differences in semen characteristics. Differences in testes size were due largely to differences in body size between species. However, no semen characteristic could be explained by allometric relationships. The three gazelle species differed in the intensity of sperm competition (as measured by relative testes mass), a factor that could explain differences in the proportion of normal spermatozoa. Finally, although the three species have reached different levels of inbreeding, this factor did not explain differences in semen characteristics in the population.

Inbreeding, fluctuating asymmetry, and ejaculate quality in an endangered ungulate.

An ever-increasing number of species are suffering marked reductions in population size as a consequence of human activities. To understand the impact of these changes it is essential to assess how small population size affects individual fitness and the viability of populations. This issue acquires special relevance among endangered species in which numbers have decreased to such an extent that captive breeding must be established with a few founders. A major risk associated with small population size is inbreeding depression. The effects of inbreeding upon male reproductive traits are the subject of an ongoing controversy, since the evidence linking lack of genetic variability and poor ejaculate quality at the population level has been criticized recently by several authors. We report that among Gazella cuvieri males, inbreeding coefficient shows a strong inverse relationship with ejaculate quality. Furthermore, the degree of fluctuating asymmetry is positively related to the coefficient of inbreeding and negatively related to the proportion of normal sperm, suggesting that it is a reliable indicator of genetic stress and of ejaculate quality.

Oestrous synchronization, semen preservation and artificial insemination in the Mohor gazelle (Gazella dama mhorr) for the establishment of a genome resource bank programme.

Gazella dama mhorr is an endangered species with an extant population of about 190 animals distributed between several zoos. Semen was collected by electro-ejaculation from 12 adult males, and cryopreserved in TEST-yolk diluent containing 6% glycerol. The effects of the concentration of egg yolk (5%, 10% and 20%) and the presence or absence of sodium triethanolamine lauryl sulfate (equex) on sperm motion and acrosomal integrity after thawing were examined. Increasing concentrations of egg yolk resulted in more acrosomal damage and poorer motility after thawing. The presence or absence of equex had no effect on either parameter. The frozen spermatozoa were used in an insemination trial, in which 13 females were treated with intravaginal progesterone-releasing devices to synchronize oestrus. Seven females were inseminated with frozen-thawed semen 48 h after removal of the devices, and six were inseminated after 60 h. Three females in the first group and one in the second group became pregnant. However, only one pregnancy (from the 48-h group) was carried to term. The study demonstrated the feasibility of applying artificial insemination in this species, but revealed that a number of outstanding technical problems remain to be solved.