55 research outputs found
Semen characteristics of free-ranging African elephants (Loxodonta africana) and Southern white rhinoceros (Ceratotherium simum simum) using Computer-aided sperm analysis, Electron microscopy and Genomics as diagnostic tools
Philosophiae Doctor - PhDThe survival of free-ranging (in situ) African elephant and Southern white rhinoceros populations are currently being challenged on a daily basis in Africa. Reproductive health is considered a vital component of species conservation. Conservation of the last mega land mammals may ultimately require intervention by breeding management or combined with assisted reproductive technologies
(ART). There is a strong case for gathering baseline information, both physiological and biological, of any species, as opportunities arise. During this study a total number of 21 ejaculates collected over two seasons from 12 free-ranging
African elephant bulls were characterised, as well as 10 ejaculates collected from 10 free-ranging Southern white rhinoceros bulls from two populations. Ejaculates were collected from adult bulls by means of electroejaculation under anaesthesia. Routine semen analysis was combined with Computer-aided sperm analysis (CASA), Computer-aided sperm morphology analysis (CASMA), Transmission electron microscopy (TEM) and Genomics as diagnostic tools. Additionally, sperm
functionality within different media was investigated and sperm subpopulation classification according to the motion pattern displayed. The results presented is based on the evaluation and classification of ≈ 45 000 individual African elephant spermatozoa and ≈ 18 000 individual Southern white rhinoceros spermatozoa.
The average elephant ejaculate contained a total number of 47 x 10⁹ spermatozoa (volume of 56 ± 38mL x concentration of 818 ± 750 x 10⁶/mL) that recorded a total motility of 81 ± 29% of which 62 ± 26% were progressively motile. CASA recorded velocities for curvilinear velocity (VCL 241 ± 58μm/s), straight-line velocity (VSL 173 ± 181μm/s) and average path velocity (VAP 201 ± 54μm/s), and kinematics at straightness of track (STR 86 ± 85%), linearity of track (LIN 67 ± 16%), amplitude of lateral head displacement (ALH 4 ± 0.75μm) and beat cross frequency (BCF 21 ± 3Hz). Structural analysis revealed 68 ± 11% of the spermatozoa were viable (intact plasma membrane) and 77 ± 11% maintained acrosome integrity. Ejaculates contained 55 ± 14% morphologically normal spermatozoa, CASMA measured sperm head lengths at 6.83 ± 0.26μm and width 3.32 ± 0.18μm (total head area
of 20.17 ± 1.96μm²) of which 38.95 ± 0.92% is covered by an acrosomal cap. The average rhinoceros ejaculate contained a total number of 1.1 x 10⁹ spermatozoa (volume of 24 ± 24mL x concentration of 83 ± 96 x 10⁶/mL) that recorded a total motility at 82 ± 8% of which 28 ± 23% were progressively motile. CASA recorded velocities for VCL (85 ± 29μm/s), VSL (44 ± 25μm/s) and VAP (69 ± 30μm/s, and kinematics at STR (63 ± 14%), LIN (51 ± 16%), ALH (2 ± 0.16μm) and BCF
(16 ± 6Hz). Structural analysis revealed 73 ± 10% of the spermatozoa were viable (intact plasma membrane) and 76 ± 4% maintained acrosome integrity. Ejaculates contained 62 ± 14% morphologically normal spermatozoa, CASMA measured sperm head lengths at 5.5 ± 0.17μm and width 2.9 ± 0.19μm (total head area of 14.8 ± 1.43μm²) of which 36.3 ± 0.59% is covered by an acrosomal cap. Based on a Boolean argument and CASA data exploration it was possible to derive elephant and rhinoceros CASA cut-off criteria to sort between activated and hyperactivated motile spermatozoa. For the genomic component of this study, the CatSper1 (Loxodonta africana) gene was identified,sequenced and verified in a free-ranging (natural) African elephant population. Multivariate analysis(MVA) was applied to examine the associations between the semen and sperm parameters and the
traits they accounted for in this study. Our understanding of wildlife reproductive sciences can substantially progress as the analytical techniques applied and the combination thereof is expanded. This investigation presents a new set of comprehensive semen and sperm threshold values for future investigations
Positive reinforcement conditioning as a tool for frequent minimally invasive blood and vaginal swab sampling in African lions (Panthera leo)
The South African National Research Foundation, the South African Veterinary Foundation and the Zebra Foundation for Veterinary Zoological Education.http://www.tandfonline.com/loi/haaw202021-12-29hj2020Anatomy and PhysiologyMammal Research Institut
Bottlenose dolphin (Tursiops truncatus) sperm revisited : motility, morphology and ultrastructure of fresh sperm of consecutive ejaculates
Computer aided sperm analysis systems allow detailed examination of sperm motility and morphology variables, which are important for the understanding of the spermatology of a species and the development of assisted reproductive techniques. Cetacean biology is too complex to study in the wild and data from captive individuals provide an important alternative for the conservation of these charismatic animals. The present study evaluates ejaculate and sperm characteristics, including sperm motility, kinematic variables and quantitative sperm morphology and ultrastructure, of consecutive ejaculates from Atlantic bottlenose dolphins (Tursiops truncatus). Sperm concentrations and total and progressive motilities were greater in the second than the first ejaculate, with all ejaculates being of very high quality (6.9–1127 × 106/ml sperm concentration, 75% to 91% total motility and 89% to 96% normal sperm). Most sperm in an ejaculate (≥84%) were highly (VCL>150 μm/s) and progressively motile with very few abnormal sperm. The sperm have small heads, a short but very bulky midpiece and a long tail. Detailed sperm morphometrics using CASA indicated there were similarities from one ejaculate to the next. The large mitochondria with extensive cristae mitochondriales are tightly packed in the midpiece resulting in a large midpiece volume. All the semen and sperm characteristics indicate high quality sperm and support the assumption that a multimale mating system is present in T. truncatus.The National Zoological Garden, South African National Biodiversity Institute, South Africahttp://www.elsevier.com/locate/anireprosci2019-08-01hj2018Production Animal StudiesZoology and Entomolog
Cardiopulmonary parameters and arterial blood gases during etorphine-medetomidine-midazolam immobilization in free-ranging black rhinoceroses (Diceros bicornis) undergoing electro-ejaculation : a preliminary study
Conservation management interventions for the critically endangered black rhinoceros
(Diceros bicornis) require immobilization, which offer opportunities for semen collection
and cryopreservation to establish genetic reservoirs. In free-ranging rhinoceroses,
a combination of the potent opioid etorphine and the tranquilizer azaperone is
routinely used for chemical immobilization but is associated with muscle rigidity and
severe cardiopulmonary changes. Additionally, azaperone inhibits semen emission.
Seven free-ranging, male, sexually mature black rhinoceroses were immobilized
with an alternative protocol consisting of 4.5mg etorphine, 5mg medetomidine,
50mg midazolam and 2,500 IU hyaluronidase delivered remotely by darting from
a helicopter. During the immobilization, electro-ejaculation was performed with
a portable electro-ejaculator, and a species-specific rectal probe. Animals were
observed for muscle tremors. Longitudinal changes in respiratory rate, heart rate
and peripheral oxyhemoglobin saturation, measured at 5min intervals, were assessed
using a general mixed model. Non-invasive oscillometric blood pressure and
arterial blood gas variables were measured at first handling and before reversal
and compared using the Wilcoxon rank sum test. All animals were successfully
immobilized, showed no muscle tremors, presented with normal heart rates and
lactate concentration (<5 mmol/L), recovered uneventfully, but experienced acidemia,
hypoxemia and hypercapnia. Induction time and total time in recumbency were
4.2 ± 0.41 and 38.4 ± 6.9min, respectively. Electro-stimulation commenced after
11.7 ± 3.98min and completed after 24.3 ± 6.65min. Semen-rich fractions were successfully collected from six animals. Our observations indicate that etorphinemedetomidine-
midazolam provides a promising immobilization protocol for free-ranging
black rhinoceroses, that allows for successful electro-ejaculation.Rhino Force SA NPChttps://www.frontiersin.org/journals/veterinary-science#am2022Production Animal Studie
Arterial blood gases and cardiorespiratory parameters in etorphine-medetomidine-midazolam immobilized free-ranging and game-farmed Southern white Rhinoceroses (Ceratotherium simum simum) undergoing electro-ejaculation
With the rapid loss of individuals in the wild, semen cryopreservation has gained
importance to safeguard the genetic diversity of white rhinoceroses (Ceratotherium
simum). For semen collection via electro-ejaculation, immobilization of free-ranging
individuals requires the potent opioid etorphine, which is routinely combined with
azaperone, but causes hypoxemia, hypercarbia, acidemia, muscle rigidity, tachycardia,
and systemic hypertension. In this study, the suitability of two alternative immobilization
protocols including etorphine, medetomidine, and midazolam at different doses (high vs.
low etorphine) was evaluated in adult white rhinoceros bulls in two different management
systems (free-ranging vs. game-farmed) and undergoing electro-ejaculation. Fourteen
free-ranging (Group 1) and 28 game-farmed rhinoceroses (Group 2) were immobilized
with ≈2.5 µg/kg etorphine (high dose), ≈2.5 µg/kg medetomidine, ≈25 µg/kg
midazolam and 1,500–1,700 IU hyaluronidase and received ≈2.5 µg/kg of butorphanol
intravenously at first handling. Twenty game-farmed animals (Group 3) received ≈1 µg/kg
etorphine (low dose), ≈5 µg/kg medetomidine, ≈25 µg/kg midazolam and 1,700 IU
hyaluronidase. Respiratory rate, heart rate and peripheral hemoglobin oxygen saturation
(SpO2) were measured at 5-min intervals; non-invasive oscillometric blood pressures
and arterial blood gases at first handling and before reversal of the immobilization;
serum clinical chemistry analytes and hematocrit at first handling. Generalized mixed
models (fixed factors: group, time, recumbency; random factor: individual rhinoceros)
were applied to compare longitudinal changes between free-ranging and game-farmed rhinoceroses immobilized with the higher etorphine dose (Groups 1 and 2), and between
the two protocols tested in the game-farmed rhinoceroses (Groups 2 and 3). All
animals were successfully immobilized, presented with normal lactate concentrations
(<5 mmol/L), experienced no muscle tremors and recovered uneventfully. Hypoxemia
and hypertension persisted throughout the immobilization in all groups. Acidemia and
hypercarbia were absent in Group 1, but present in the game-farmed animals. The
lower etorphine dose in Group 3 resulted in significantly longer induction times, however,
tachycardia was not observed. SpO2 was higher for sternal vs. lateral recumbency.
Semen-rich fractions were recovered following electro-stimulation in 46 out of the
62 animals. Our findings suggest that etorphine-medetomidine-midazolam provides
effective immobilization with fewer side effects compared to previous reports in white
rhinoceroses and is suitable for successful electro-ejaculation.Rhino Force
SA NPChttps://www.frontiersin.org/journals/veterinary-sciencedm2022Mammal Research InstituteProduction Animal Studie
Interspecific hybridization between greater kudu and nyala
Hybridization of wildlife species, even in the
absence of introgression, is of concern due to wasted
reproductive effort and a reduction in productivity. In this
study we detail an accidental mating between a female
nyala (Tragelaphus angasii) and a male greater kudu (T.
strepsiceros). The hybrid was phenotypically nyala and
was identified as such based on mitochondrial DNA. Further
genetic analysis based on nine microsatellite markers,
chromosome number and chromosome morphology however,
confirmed its status as an F1 hybrid. Results obtained
from a reproductive potential assessment indicated that this
animal does not have the potential to breed successfully
and can be considered as sterile.http://link.springer.com/journal/10709hb201
Effects of GnRH vaccination in wild and captive African Elephant bulls (Loxodonta africana) on reproductive organs and semen quality
OBJECTIVES:
Although the African elephant (Loxodonta africana) is classified as endangered by the International
Union for Conservation of Nature (IUCN), in some isolated habitats in southern Africa,
contraception is of major interest due to local overpopulation. GnRH vaccination has been
promoted as a non-invasive contraceptive measure for population management of overabundant
wildlife. We tested the efficacy of this treatment for fertility control in elephant bulls.
METHODS:
In total, 17 male African elephants that were treated with a GnRH vaccine were examined in
two groups. In the prospective study group 1 (n = 11 bulls, ages: 8±36 years), semen quality,
the testes, seminal vesicles, ampullae and prostate, which were all measured by means of
transrectal ultrasound, and faecal androgen metabolite concentrations were monitored over
a three-year period. Each bull in the prospective study received 5 ml of Improvac® (1000 μg
GnRH conjugate) intramuscularly after the first examination, followed by a booster six
weeks later and thereafter every 5±7 months. In a retrospective study group (group 2, n = 6,
ages: 19±33 years), one examination was performed on bulls which had been treated with
GnRH vaccine for 5±11 years.
RESULTS:
In all bulls of group 1, testicular and accessory sex gland sizes decreased significantly after
the third vaccination. In six males examined prior to vaccination and again after more than
five vaccinations, the testis size was reduced by 57.5%. Mean testicular height and length
decreased from 13.3 ± 2.6 cm x 15.2 ± 2.8 cm at the beginning to 7.6 ± 2.1 cm x 10.2 ± 1.8
cm at the end of the study. Post pubertal bulls (>9 years, n = 6) examined prior to vaccination
produced ejaculates with viable spermatozoa (volume: 8±175 ml, sperm concentration:
410-4000x106/ml, total motility: 0±90%), while after 5±8 injections, only 50% of these bulls
produced ejaculates with a small number of immotile spermatozoa. The ejaculates of group
2 bulls (vaccinated >8 times) were devoid of spermatozoa. Faecal androgen metabolite concentrations
measured in captive males decreased significantly after the fourth vaccination.
None of the males entered musth during the treatment period.
CONCLUSIONS:
Our results showed a marked decrease in semen quality, testicle and secondary sex gland
sizes following repeated GnRH vaccinations. After 2±4 years of continuous treatment every
5±7 months, the effects were similar to surgical castration.ISIScopu
Testicular disorder of sexual development with cryptorchidism, penile hypoplasia and hypospadias in a giraffe (Giraffa camelopardalis giraffa)
Disorders of sexual development (DSD) in wild mammals are rarely described. A male South
African giraffe (Giraffa camelopardalis giraffa) was identified with bilateral cryptorchidism.
The testes were intra-abdominal, smaller and less ovoid than in normal male giraffes. The
right testis was situated more cranially than the left and connected to a longer deferent duct
with normal ampullae. One distended vesicular gland filled with mucoid material was
identified. A short penis, situated in the perineal area, was directed caudally and presented
hypospadias. Histologically, testicular hypoplasia was present; the epididymis tubules
contained no spermatozoa and the deferent duct and vesicular gland were inflamed.
The blood testosterone concentration was 16.27 nmol/L and oestrone sulphate concentration
was 0.03 ng/mL. The aetiology of the abnormalities is unknown.http://www.jsava.co.zaam2020Paraclinical SciencesProduction Animal Studie
Sexual selection and endocrine profiles in wild South African giraffe (Giraffa camelopardalis giraffa)
No abstract available.National Research Foundation,
The Natural Wildlife Bridge,
Rockwood Conservation,
Save the Giraffes,
University of the Free State.http://www.wileyonlinelibrary.com/journal/ajehj2022Anatomy and PhysiologyCentre for Veterinary Wildlife StudiesMammal Research InstituteZoology and Entomolog
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