Evidence that hyperprolactinaemia is associated with ovarian acyclicity in female zoo African elephants

Dow, T.L.; Brown, Janine L.

doi:10.1071/rd11302

Cited by 26 publications

(19 citation statements)

References 46 publications

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“…Our Case 1 showed overt signs of pseudopregnancy, with breast development, milk secretion and, finally, mastitis; these symptoms have been described in association with hyperprolactinemia in African elephants (Yamamoto et al, 2010). However, in African elephants, elevated PRL levels are associated with complete absence of cyclicity ("flatlining"; Dow and Brown, 2012;Yamamoto et al, 2010). In contrast to Asian elephants with no clear pattern during the estrus cycle (Carden et al, 1998), in African elephants PRL levels are higher during the follicular phase compared to the luteal phase (Bechert et al, 1999).…”

Section: Discussionmentioning

confidence: 61%

Prolonged luteal lifespan and pseudopregnancy in Asian elephants (Elephas maximus)

Niemuller¹,

Steinmetz

Bouts³

et al. 2018

Animal Reproduction Science

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Pseudopregnancy is a physiological occurrence in mammals which have copulation induced ovulation, but is rarely described in spontaneous ovulating species. In this study, three cases of prolonged luteal lifespan are reported in non-pregnant Asian elephants (Elephas maximus). Case 1 was a 25-year-old female that had produced three calves previously; Case 2 was a nulliparous and 32-year-old at the start of the pseudopregnancy episode; and Case 3 occurred in a 49-year-old nulliparous elephant. Serum progesterone metabolite concentrations remained elevated for 10 months in Case 1. Urinary progestagens were high for >16 months in Case 2 and for five months in Case 3. In Case 1, multiple persistent corpora lutea were visualized monthly by ultrasonography. In all three cases, uterine leiomyoma were present and progestagen concentrations decreased spontaneously. In Case 1, the elephant became pregnant 3 years later, whilst with Case 2, the female resumed estrous cycling normally, and for the Case 3 female, there was continuation with another prolonged luteal phase before ovarian function was purposely suppressed. These examples indicate that persistently elevated progestagen concentrations may not always be indicative of pregnancy in elephants. The reasons for prolonged luteal lifespan are not understood, although serum prolactin concentrations quantified in the Case 1 female were elevated compared to values from previous reports and two other herd mates. Furthermore, all three elephants had varying degrees of uterine pathologies. It is believed that the resulting damage to the endometrium may have led to a reaction similar to implantation, which includes prolactin secretion. Prolactin may exert luteotropic properties and is thought to initiate luteal rescue during pregnancy in elephants.

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Section: Discussionmentioning

confidence: 61%

Prolonged luteal lifespan and pseudopregnancy in Asian elephants (Elephas maximus)

Niemuller¹,

Steinmetz

Bouts³

et al. 2018

Animal Reproduction Science

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“…Hyperprolactinemia for African elephants was defined as an average prolactin concentration over the 12-month sampling period of ≥18 ng/ml, similar to Prado-Oviedo et al [ 8 ], which lacked a temporal pattern [ 19 ]. Cut-off values were calculated for Asian elephants and determined to be < or ≥14 ng/ml.…”

Section: Methodsmentioning

confidence: 99%

“…One association with ovarian acyclicity in African elephants is a hormonal imbalance–hyperprolactinemia [ 10 , 18 , 19 ]. In other species, hyperprolactinemia is associated with infertility [ 20 – 22 ], and in women it is the most common disorder of the hypothalamic-pituitary axis; up to 40% presenting with secondary amenorrhea are hyperprolactinemic [ 23 , 24 ].…”

Section: Introductionmentioning

confidence: 99%

Reproductive Health Assessment of Female Elephants in North American Zoos and Association of Husbandry Practices with Reproductive Dysfunction in African Elephants (Loxodonta africana)

et al. 2016

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As part of a multi-institutional study of zoo elephant welfare, we evaluated female elephants managed by zoos accredited by the Association of Zoos and Aquariums and applied epidemiological methods to determine what factors in the zoo environment are associated with reproductive problems, including ovarian acyclicity and hyperprolactinemia. Bi-weekly blood samples were collected from 95 African (Loxodonta africana) and 75 Asian (Elephas maximus) (8–55 years of age) elephants over a 12-month period for analysis of serum progestogens and prolactin. Females were categorized as normal cycling (regular 13- to 17-week cycles), irregular cycling (cycles longer or shorter than normal) or acyclic (baseline progestogens, <0.1 ng/ml throughout), and having Low/Normal (<14 or 18 ng/ml) or High (≥14 or 18 ng/ml) prolactin for Asian and African elephants, respectively. Rates of normal cycling, acyclicity and irregular cycling were 73.2, 22.5 and 4.2% for Asian, and 48.4, 37.9 and 13.7% for African elephants, respectively, all of which differed between species (P < 0.05). For African elephants, univariate assessment found that social isolation decreased and higher enrichment diversity increased the chance a female would cycle normally. The strongest multi-variable models included Age (positive) and Enrichment Diversity (negative) as important factors of acyclicity among African elephants. The Asian elephant data set was not robust enough to support multi-variable analyses of cyclicity status. Additionally, only 3% of Asian elephants were found to be hyperprolactinemic as compared to 28% of Africans, so predictive analyses of prolactin status were conducted on African elephants only. The strongest multi-variable model included Age (positive), Enrichment Diversity (negative), Alternate Feeding Methods (negative) and Social Group Contact (positive) as predictors of hyperprolactinemia. In summary, the incidence of ovarian cycle problems and hyperprolactinemia predominantly affects African elephants, and increases in social stability and feeding and enrichment diversity may have positive influences on hormone status.

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“…Prolactin is folliculogenic in many species and in African elephants is elevated during the follicular phase (Bechert et al ., ; Yamamoto et al ., ; Dow & Brown, ). Interestingly, no secretory prolactin pattern is observed across the oestrous cycle in Asian elephants (Brown, Walker & Moeller, ), representing a species difference that has relevance to observations of abnormal prolactin secretion, which is commonly observed in African but not Asian elephants (Brown, ).…”

Section: Reproductionmentioning

confidence: 99%

“…One association with ovarian acyclicity in African elephants is hyperprolactinemia (Brown, Walker et al ., ; Yamamoto et al ., ; Dow & Brown, ), a common disorder of the hypothalamic–pituitary axis related to infertility in women (Wang et al ., ), and a hormone associated with stress (Torner, ). Asian elephant females rarely present with hyperprolactinemia, whereas over half of acyclic African elephants are hyperprolactinemic (Brown, Walker et al ., ).…”

Section: Reproductionmentioning

confidence: 99%

Zoo elephant research: contributions to conservation of captive and free‐ranging species

Bechert

Brown

Dierenfeld

et al. 2019

International Zoo Yearbook

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African elephants Loxodonta africana and Asian elephants Elephas maximus are not thriving in many captive settings and are threatened throughout their native ranges. Many zoos support in situ conservation projects and provide opportunities to conduct ex situ research in controlled settings with comparably approachable animals. Zoo elephant projects may facilitate fieldwork with free‐ranging elephants (e.g. development of non‐invasive sampling and analytical tools), which may then also improve the husbandry of elephants in human care. Free‐ranging elephants also benefit from drug therapies and veterinary care when they are orphaned, kept as working elephants or brought in as rehabilitation cases – especially as human–elephant conflicts become more common as a result of ever‐expanding human populations. Much has been learned about the basic biology and husbandry needs of elephants but, often, the more we learn, the more questions arise. There are physiological differences between African and Asian elephants, and this should affect the management of these animals. This paper will provide brief overviews of the current state of knowledge regarding the pharmacology, nutrition, reproduction, sensory biology and diseases (primarily elephant endotheliotropic herpesvirus infections) relevant to elephants with recommendations for future research.

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Evidence that hyperprolactinaemia is associated with ovarian acyclicity in female zoo African elephants

Cited by 26 publications

References 46 publications

Prolonged luteal lifespan and pseudopregnancy in Asian elephants (Elephas maximus)

Prolonged luteal lifespan and pseudopregnancy in Asian elephants (Elephas maximus)

Reproductive Health Assessment of Female Elephants in North American Zoos and Association of Husbandry Practices with Reproductive Dysfunction in African Elephants (Loxodonta africana)

Zoo elephant research: contributions to conservation of captive and free‐ranging species

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