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L. S. Doughty - One of the best experts on this subject based on the ideXlab platform.

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Barbara S. Durrant - One of the best experts on this subject based on the ideXlab platform.

  • VAGINOSCOPIC IDENTIFICATION OF A VERTICAL VAGINAL SEPTUM IN ONE PRIMIPAROUS AND THREE NULLIPAROUS SOUTHERN WHITE RHINOCEROS (Ceratotherium simum simum).
    Journal of zoo and wildlife medicine : official publication of the American Association of Zoo Veterinarians, 2019
    Co-Authors: Matthew E Kinney, Dean A. Hendrickson, Jeffery R. Zuba, Meredith M Clancy, Parker M. Pennington, Lauren L. Howard, Rebecca Papendick, Barbara S. Durrant
    Abstract:

    Vaginoscopy using a 10-mm, 30° forward viewing rigid endoscope was used to evaluate the caudal reproductive tract of four subadult southern white rhinoceros (Ceratotherium simum simum). A vertical vaginal septum was documented in all four animals, including a primiparous cow that gave birth to a stillborn calf 14 months before vaginoscopy. Vaginoscopy using a 57-cm-long, 10-mm, 30° forward viewing endoscope provides adequate visualization of the caudal reproductive track in the southern white rhinoceros, and a detailed description of the vertical vaginal septum is presented. Additionally, the presence of a vertical vaginal septum in a primiparous southern white rhinoceros suggests the presence of this anatomic structure cannot be used as a proxy of nulliparity for captive southern white rhinoceros.

  • Ovulation induction in anovulatory southern white rhinoceros (Ceratotherium simum simum) without altrenogest.
    Conservation physiology, 2019
    Co-Authors: Parker M. Pennington, Kira L. Marshall, Jonnie M Capiro, Rachel G. Felton, Barbara S. Durrant
    Abstract:

    All species in the extant Rhinocerotidae family are experiencing increased threats in the wild, making captive populations essential genetic reservoirs for species survival. However, managed species face distinct challenges in captivity, resulting in populations that are not self-sustaining. Captive southern white rhinoceros (Ceratotherium simum simum) have low reproductive rates and presumed acyclicity is common among females. Although many females fail to ovulate, follicle growth may occur and ovulation can be hormonally induced. Female southern white rhino (n = 6), housed as a bachelorette group, were determined to be ovulatory (n = 1) or anovulatory (n = 5) by serial ultrasound and fecal progestagen analysis. When follicles reached pre-ovulatory size (~35 mm), females (n = 4) were induced to ovulate in 11 trials with a GnRH analog (4.5 mg, SucroMate™) via single intramuscular injection. Nine trials resulted in ovulation (81.8%), all between 36 and 48 hours post-treatment. Ovulations were confirmed by progestagen elevation above baseline coincident with visualization of a corpus luteum (CL). Luteal phases were characterized as short (

  • 97 Ovulation induction in anovulatory southern white rhinoceros (Ceratotherium simum simum)
    Reproduction Fertility and Development, 2019
    Co-Authors: Parker M. Pennington, Jonnie M Capiro, K. Marshall, R. Felton, Barbara S. Durrant
    Abstract:

    The extant Rhinocerotidae family is experiencing threats in the wild, making captive populations important genetic reservoirs for species survival. Because each species faces distinct challenges in captivity, populations are not self-sustaining. Therefore, assisted reproductive technologies (ART) such as AI will be necessary to maintain or increase captive genetic variation. Captive-born female white rhinoceros (Ceratotherium simum simum) have low reproductive rates and apparent acyclicity is a common issue. Although females fail to ovulate and progesterone remains at baseline levels, follicle growth may occur and ovulation can be induced with exogenous hormones. Female southern white rhinos (n = 6) housed as a bachelorette group were determined to be ovulatory (n = 1) or anovulatory (n = 5) by serial ultrasound and fecal progesterone (P4; ng g−1) analysis. However, all anovulatory females grew follicles beyond preovulatory size, which then regressed. At the time of study, when follicles were preovulatory size (35.4 ± 1.2 mm; mean ± SD), anovulatory females (n = 4) were induced to ovulate (n = 11) with a gonadotropin releasing hormone (GnRH) agonist (4.5 mg, SucroMate™; Bioniche Animal Health, Bogart, GA, USA) in a single intramuscular injection. Nine treatments resulted in ovulation (81.8%), all between 36 and 48 h post-treatment, while 2 hemorrhagic anovulatory follicles (18.2%; HAF) formed, both in the same female. Ovulations were confirmed by disappearance of the follicle by 48 h and P4 elevation above baseline was coincident with corpus luteum (CL) and HAF formation. All resulting luteal structures were included in analysis. Follicle growth was permitted to proceed without GnRH treatment between inductions (n = 6); dominant follicles grew beyond preovulatory size (43.8 ± 6.1 mm) followed by regression and growth of another preovulatory follicle that was subjected to GnRH treatment. Data were analyzed by R studio (ver. 1.1.383). Luteal phases were characterized as “short” ( 50 days). Only P4 above baseline (days) was significantly different (P 

  • ovulation induction in anovulatory southern white rhinoceros Ceratotherium simum simum without altrenogest
    Conservation Physiology, 2019
    Co-Authors: Parker M. Pennington, Kira L. Marshall, Jonnie M Capiro, Rachel G. Felton, Barbara S. Durrant
    Abstract:

    All species in the extant Rhinocerotidae family are experiencing increased threats in the wild, making captive populations essential genetic reservoirs for species survival. However, managed species face distinct challenges in captivity, resulting in populations that are not self-sustaining. Captive southern white rhinoceros (Ceratotherium simum simum) have low reproductive rates and presumed acyclicity is common among females. Although many females fail to ovulate, follicle growth may occur and ovulation can be hormonally induced. Female southern white rhino (n = 6), housed as a bachelorette group, were determined to be ovulatory (n = 1) or anovulatory (n = 5) by serial ultrasound and fecal progestagen analysis. When follicles reached pre-ovulatory size (~35 mm), females (n = 4) were induced to ovulate in 11 trials with a GnRH analog (4.5 mg, SucroMate™) via single intramuscular injection. Nine trials resulted in ovulation (81.8%), all between 36 and 48 hours post-treatment. Ovulations were confirmed by progestagen elevation above baseline coincident with visualization of a corpus luteum (CL). Luteal phases were characterized as short (<50 days) or long (≥50 days). Between short and long cycles, only the number of days of progestagen above baseline was significantly different (P < 0.05), while days with visible luteal structures was not significant (P = 0.11). Both cycle types were observed following both spontaneous and induced ovulations. Furthermore, we showed that longer cycle lengths do not necessarily indicate early pregnancy loss as none of the females were bred or inseminated during the study. While anovulation is common in the southern white rhino captive population, ovulation induction can be achieved efficiently and predictably for use in conjunction with artificial insemination or to facilitate natural breeding. This information will lead to more efficient use of assisted reproductive technologies to overcome reproductive challenges in this species and to generate genetically healthy captive populations as a hedge against extinction.

  • Reproductive performance parameters in a large population of game-ranched white rhinoceroses (Ceratotherium simum simum).
    PloS one, 2017
    Co-Authors: Cyrillus Ververs, Martine Van Zijll Langhout, Miel Hostens, Michelle Otto, Jan Govaere, Barbara S. Durrant, Ann Van Soom
    Abstract:

    The population of free-roaming white rhinoceroses (Ceratotherium simum) is under serious threat. Captive breeding of this species is therefore becoming more important, but this is challenging and often not successful. Obtaining reproductive reference values is a crucial aspect of improving these breeding results. In this study performed between 2008 and 2016, reproductive performance was analysed in 1,354 animals kept in a 8000 hectares game-ranched environment. Descriptive statistics of this captive population showed an average annual herd growth (%) of 7 .0±0.1 (min -9 -max 15). Average calving rates were calculated as an annual calving rate of 20% and biennial calving rate of 37% adult females calving per year. Females had a median age of 83.2 months at first calving (IQR 72.9-110.7) and inter-calving intervals of 29.2 (IQR 24.6-34.8) months. Furthermore, translocations of animals did not interfere with reproductive success in terms of inter-calving periods or age at first calving. Multivariate models showed a clear seasonal calving pattern with a significant increase of the number of calvings during December-April when compared to April-December. Our results did not show any significant skewed progeny sex ratios. Weather observations showed no significant influence of rain or season on sex ratios of the calves.

T. Avent - One of the best experts on this subject based on the ideXlab platform.

Robert Hermes - One of the best experts on this subject based on the ideXlab platform.

  • Contrasting evolutionary history, anthropogenic declines and genetic contact in the northern and southern white rhinoceros (Ceratotherium simum)
    Proceedings. Biological sciences, 2018
    Co-Authors: Yoshan Moodley, Robert Hermes, Isa-rita M. Russo, Jan Robovský, Desiré L. Dalton, Antoinette Kotze, Steve Smith, Jan Stejskal, Oliver A. Ryder, Chris Walzer
    Abstract:

    The white rhinoceros (Ceratotherium simum) has a discontinuous African distribution, which is limited by the extent of sub-Saharan grasslands. The southern population (SWR) declined to its lowest n...

  • Female white (Ceratotherium simum simum) and Greater one-horned (GOH) (rhinoceros unicornis) rhinoceroses treated with GnRF vaccine.
    2016
    Co-Authors: Robert Hermes, Franz Schwarzenberger, Frank Göritz, Teresa Fernandes, Rui Bernardino, Antoine Leclerc, Eva Greunz, Abraham Mathew, Sarah Forsyth
    Abstract:

    Female white (Ceratotherium simum simum) and Greater one-horned (GOH) (rhinoceros unicornis) rhinoceroses treated with GnRF vaccine.

  • CLINICAL MANAGEMENT OF BILATERAL CUTANEOUS SQUAMOUS CELL CARCINOMA OF THE HIND FEET PADS IN A SOUTHERN WHITE RHINOCEROS (Ceratotherium simum simum)
    Journal of zoo and wildlife medicine : official publication of the American Association of Zoo Veterinarians, 2016
    Co-Authors: Eva Maria Greunz, Robert Hermes, Marie Simon, Karin Lemberger, Gabriela Galateanu, Antoine Leclerc
    Abstract:

    Abstract The current report describes the temporary regression, due to intensive symptomatic treatment, of ulcerative skin lesions caused by squamous cell carcinoma in a white rhinoceros. A captive, 40-yr-old southern white rhinoceros (Ceratotherium simum simum) developed profound, ulcerative skin lesions on the pads of both hind feet. At the peak of the disease, at least one quarter of the pads was affected. A diagnosis of squamous cell carcinoma was made via biopsy. Treatment included anti-inflammatory drugs, antibiotics, and local care. The lesions regressed on both feet until they seemed clinically healed. It was presumed that long-term, anti-inflammatory treatment and local bandaging had induced the temporary regression of the lesions. Two years later, however, a small ulcerative lesion reappeared on one pad and post mortem examination confirmed that the carcinoma was also histologically present in the clinically intact tissue. No metastasis was found and computed tomography showed normal digital bones.

  • Estrus induction in white rhinoceros (Ceratotherium simum)
    Theriogenology, 2012
    Co-Authors: Robert Hermes, Thomas B Hildebrandt, Frank Göritz, Chris Walzer, Charlie Gray, Cheryl Niemuller, Franz Schwarzenberger
    Abstract:

    The estrous cycle length in the white rhinoceros (Ceratotherium simum) is either 4 or 10 wk. The cause(s) for this variation as well as the poor fertility rate in captivity remains under debate in this species. Most captive adult white rhinoceros undergo long anovulatory periods without luteal activity which are considered a major reason for their low reproductive rate. In this study, the synthetic progestin chlormadinone acetate (CMA) was tested in combination with hCG or the GnRH analogue deslorelin for its efficiency to induce ovulation in fourteen females without luteal activity and in three, regular cycling females. HCG (N = 12), injectable GnRH analogue (N = 8) and GnRH analogue implants (N = 15) were given to induce ovulation after CMA treatment. Treatment success was determined using both transrectal ultrasonography and progesterone metabolite EIA analysis. A preovulatory sized follicle (3.5 ± 0.1 cm) or a corpus luteum (5.1 ± 0.7) was present on the ovary one day after induction in 93.1% of the treatments. Despite this high rate of ovarian response, ovulation rate differed between the study groups. The ovulation rate for hCG, injectable GnRH analogue and GnRH analogue implants was 66.7%, 62.5% and 93.3%, respectively. Ovulation rate in cyclic females treated with GnRH implants was 100% (6/6) compared with 89% (8/9) in females without luteal activity receiving the same treatment. The length of the estrous cycle when induced with hCG was 4 wk (85.7%). The estrous cycle when induced with GnRH analogue was predominantly 10 wk long. Two females without luteal activity treated with GnRH became pregnant. In conclusion, CMA in combination with GnRH analogue implants was highly effective to induce ovulation in white rhinoceroses and thus can contribute to efforts aimed at increasing natural mating and reproductive rates in the captive white rhinoceros population.

  • Analysis of the European captive Southern white rhinoceros Ceratotherium simum simum population using the International Studbook for the African White Rhinoceros (2001–2004) and integrating reproductive health findings
    International Zoo Yearbook, 2012
    Co-Authors: C.e. Reid, L. Versteege, A. Ludwig, Robert Hermes
    Abstract:

    The goal of ex situ conservation is to maintain genetic diversity, avoid inbreeding and maximize equal representation of founder individuals. Analysis of a well-maintained studbook yields important data concerning fertility and mortality that is invaluable to ex situ conservation. To evaluate the reproductive status of the European captive Southern white rhinoceros Ceratotherium simum simum population, basic demographics and population parameters were calculated using the International Studbook for the African White RhinocerosCeratotherium simum (2001–2004) data with the integration of recent scientific findings regarding reproductive health of individuals within the ‘reproductive age’. Kinship analysis of the 2001–2004 population was also performed to evaluate genetic diversity. Results indicated the population is declining 1·19 times faster than it is growing. To realize a 1% population increase at the 2001–2004 death rate, reproduction would have to increase by 214%. It is necessary to increase the genetically contributing subpopulation and to achieve a reproduction capacity that surpasses the rate currently possible with natural mating.