scholarly journals Ovulation, pregnancy, placentation and husbandry in the African elephant ( Loxodonta africana )

2006 ◽  
Vol 361 (1469) ◽  
pp. 821-834 ◽  
Author(s):  
W.R Allen
Keyword(s):  
South Africa ◽  
Population Density ◽  
Blood Vessel ◽  
Ferric Iron ◽  
Loxodonta Africana ◽  
African Elephant ◽  
Corpora Lutea ◽  
Gestation Length ◽  
In Captivity ◽  
In The Wild

The African elephant reproduces so efficiently in the wild that overpopulation is now a serious problem in some game parks in Zimbabwe, Botswana and South Africa. The female reaches puberty between 10 and 12 years of age in the wild and, when in captivity, shows oestrous cycles of 14–15 weeks duration. She readily conceives a singleton in the wild yet her uterus has the capacity for twins. She shows a gestation length of 22 months and, in the wild, shows a population density and feed dependent intercalving interval of 4–8 years. The trophoblast erodes the lumenal epithelium of the endometrium and stimulates upgrowths of blood vessel-containing stromal villi, which develop eventually into the broad, tightly folded lamellae of the zonary, endotheliochorial placenta. Significant quantities of leaked maternal erythrocytes and ferric iron are phagocytosed by specialized trophoblast cells in the haemophagous zones at the lateral edges of the placental band. Although the placenta itself is endocrinologically inert, the foetal gonads, which enlarge greatly during the second half of pregnancy can synthesize 5α-dihydryoprogesterone and other 5α pregnane derivatives from cholesterol and pregnenolone. These products may synergize with progestagens secreted by the 2–8 large corpora lutea which are always present in the maternal ovaries throughout gestation to maintain the pregnancy state.

scholarly journals Changes in African Elephant (Loxodonta africana) faecal steroid concentrations post-defaecation

Bothalia ◽  
2018 ◽  
Vol 48 (1) ◽  
Author(s):  
Judith T. Webber ◽  
Michelle D. Henley ◽  
Yolanda Pretorius ◽  
Michael J. Somers ◽  
Andre Ganswindt
Keyword(s):  
Reproductive Function ◽  
Loxodonta Africana ◽  
African Elephant ◽  
Sample Collection ◽  
Male And Female ◽  
Freeze Dried ◽  
Metabolite Concentrations ◽  
Endocrine Status ◽  
In The Wild ◽  
Sun And Shade

Background: Faecal hormone metabolite measurement is a widely used tool for monitoring reproductive function and response to stressors in wildlife. Despite many advantages of this technique, the delay between defaecation, sample collection and processing may influence steroid concentrations, as faecal bacterial enzymes can alter steroid composition post-defaecation.Objectives: This study investigated changes in faecal glucocorticoid (fGCM), androgen (fAM) and progestagen (fPM) metabolite concentrations in faeces of a male and female African elephant (Loxodonta africana) post-defaecation and the influence of different faeces-drying regimes.Method: Subsamples of fresh faeces were frozen after being dried in direct sun or shade for 6, 20, 24, 48 and 72 h and 7 and 34 days. A subset of samples for each sex was immediately frozen as controls. Faecal hormone metabolite concentrations were determined using enzyme immunoassays established for fGCM, fAM and fPM monitoring in male and female African elephants.Results: Hormone metabolite concentrations of all three steroid classes were stable at first, but changed distinctively after 20 h post-defaecation, with fGCM concentrations decreasing over time and fPM and fAM concentrations steadily increasing. In freeze-dried faeces fGCM concentrations were significantly higher than respective concentrations in sun-dried material, which were in turn significantly higher than fGCM concentrations in shade-dried material. In contrast, fAM concentrations were significantly higher in sun- and shade-dried faeces compared to freeze-dried faeces. Higher fPM concentrations were also found in air-dried samples compared to lyophilised faeces, but the effect was only significant for sun-dried material.Conclusion: The revealed time restriction for collecting faecal material for hormone monitoring from elephants in the wild should be taken into account to assure reliable and comparable results. However, if logistics allow a timely collection, non-invasive hormone measurement remains a powerful and reliable approach to provide information about an elephant’s endocrine status.

Observations on Activity Patterns, Population and Den Characteristics of The Water Rat Hydromys chrysogaster Along Badger Creek, Victoria.

1995 ◽  
Vol 18 (1) ◽  
pp. 71
Author(s):  
J.L. Gardner ◽  
M. Serena
Keyword(s):  
Population Density ◽  
Activity Patterns ◽  
Home Ranges ◽  
Adult Males ◽  
Fish Farms ◽  
Age Classes ◽  
Irrigation Channels ◽  
In Captivity ◽  
In The Wild ◽  
Hydromys Chrysogaster

The Water Rat Hydromys chrysogaster is Australia's largest amphibious rodent, occupying freshwater rivers, lakes, and coastal and estuarine habitats throughout the continent (Watts and Aslin 1981). Little is known of the species' social organisation or use of space in the wild although Harris (1978) suggested that adults might be intrasexually aggressive. The home ranges of all sex and age classes overlap to some extent but home ranges of adults of the same sex appear to overlap less (Harris 1978). Adult males occupy the largest home ranges which overlap those of one or more females. In captivity individuals kept in groups form hierarchies in which only the dominant females usually breed successfully (Olsen 1982). Fighting occurs primarily among males, with the highest incidence of injuries observed at the beginning of the main September-March breeding season (Olsen 1980, 1982). The results of trapping studies indicate that population density may vary considerably, with the greatest numbers of animals typically occupying man-modified habitats such as irrigation channels or fish farms (McNally 1960, Watts and Aslin 1981, Smales 1984). Aggressive behaviour appears to be related to pelage colour (phenotype) and population density; the higher the density the greater the number of injured individuals (Olsen 1980).

scholarly journals Changes in African Elephant (Loxodonta africana) faecal steroid concentrations post-defaecation

Bothalia ◽  
2018 ◽  
Vol 48 (2) ◽  
Author(s):  
Judith T. Webber ◽  
Michelle D. Henley ◽  
Yolanda Pretorius ◽  
Michael J. Somers ◽  
Andre Ganswindt
Keyword(s):  
Reproductive Function ◽  
Loxodonta Africana ◽  
African Elephant ◽  
Sample Collection ◽  
Male And Female ◽  
Freeze Dried ◽  
Metabolite Concentrations ◽  
Endocrine Status ◽  
In The Wild ◽  
Sun And Shade

Background: Faecal hormone metabolite measurement is a widely used tool for monitoring reproductive function and response to stressors in wildlife. Despite many advantages of this technique, the delay between defaecation, sample collection and processing may influence steroid concentrations, as faecal bacterial enzymes can alter steroid composition post-defaecation.Objectives: This study investigated changes in faecal glucocorticoid (fGCM), androgen (fAM) and progestagen (fPM) metabolite concentrations in faeces of a male and female African elephant (Loxodonta africana) post-defaecation and the influence of different faeces-drying regimes.Method: Subsamples of fresh faeces were frozen after being dried in direct sun or shade for 6, 20, 24, 48 and 72 h and 7 and 34 days. A subset of samples for each sex was immediately frozen as controls. Faecal hormone metabolite concentrations were determined using enzyme immunoassays established for fGCM, fAM and fPM monitoring in male and female African elephants.Results: Hormone metabolite concentrations of all three steroid classes were stable at first, but changed distinctively after 20 h post-defaecation, with fGCM concentrations decreasing over time and fPM and fAM concentrations steadily increasing. In freeze-dried faeces fGCM concentrations were significantly higher than respective concentrations in sun-dried material, which were in turn significantly higher than fGCM concentrations in shade-dried material. In contrast, fAM concentrations were significantly higher in sun- and shade-dried faeces compared to freeze-dried faeces. Higher fPM concentrations were also found in air-dried samples compared to lyophilised faeces, but the effect was only significant for sun-dried material.Conclusion: The revealed time restriction for collecting faecal material for hormone monitoring from elephants in the wild should be taken into account to assure reliable and comparable results. However, if logistics allow a timely collection, non-invasive hormone measurement remains a powerful and reliable approach to provide information about an elephant’s endocrine status.

Different origins of two corpora lutea recovered from a pregnant African elephant (Loxodonta africana )

2017 ◽  
Vol 52 (6) ◽  
pp. 1138-1141 ◽  
Author(s):  
Y Yamamoto ◽  
K Nagaoka ◽  
Y Kamite ◽  
G Watanabe ◽  
T Allen ◽  
...  
Keyword(s):  
Loxodonta Africana ◽  
African Elephant ◽  
Corpora Lutea ◽  
Different Origins

scholarly journals BIOCHEMICAL OBSERVATIONS ON THE CORPORA LUTEA OF THE AFRICAN ELEPHANT, LOXODONTA AFRICANA

Reproduction ◽  
1969 ◽  
Vol 20 (1) ◽  
pp. 111-117 ◽  
Author(s):  
J. G. SMITH ◽  
J. HANKS ◽  
R. V. SHORT
Keyword(s):  
Loxodonta Africana ◽  
African Elephant ◽  
Corpora Lutea

scholarly journals Luteal maintenance of pregnancy in the African elephant (Loxodonta africana)

Reproduction ◽  
2012 ◽  
Vol 143 (6) ◽  
pp. 845-854 ◽  
Author(s):  
F J Stansfield ◽  
W R Allen
Keyword(s):  
Loxodonta Africana ◽  
Hydroxysteroid Dehydrogenase ◽  
Interstitial Cells ◽  
African Elephant ◽  
Oestrous Cycle ◽  
Degenerative Changes ◽  
Gestation Period ◽  
Placental Lactogen ◽  
Corpora Lutea ◽  
Luteal Cells

The ovaries of eight African elephant foetuses and their mothers between 2 and 22 months of gestation, and those of two cycling and two lactating elephants, were examined grossly, histologically and immunocytochemically, with emphasis on the development and regression of accessory corpora lutea (CL) of pregnancy and the steroidogenic capacities of the accessory CL and the foetal ovaries. The results supported recent findings that the accessory CL form as a result of luteinisation, with and without ovulation, of medium-sized follicles during the 3-week inter-luteal period of the oestrous cycle. They enlarge significantly and become steroidogenically active around 5 weeks of gestation, probably in response to the placental lactogen which is secreted by the implanting trophoblast of the conceptus. The large luteal cells stained strongly for 3β hydroxysteroid dehydrogenase (3βHSD) activity throughout the 22-month gestation period although they showed vacuolation and other degenerative changes in the final months of gestation coincident with hypertrophy and hyperplasia of 3βHSD-positive interstitial cells in the foetal gonads. It is proposed that the progestagens secreted by the enlarged gonads of the elephant foetus may function both to assist the maternal ovaries in supporting the pregnancy state and to induce torpor and intrauterine immobility of the rapidly growing foetus.

Sign in / Sign up

Export Citation Format

Share Document