Comparative endocrinology of cycling and non-cycling Asian (Elephas maximus) and African (Loxodonta africana) elephants

Brown, Janine L.; Walker, Susan L.; Moeller, Tanya

doi:10.1016/j.ygcen.2004.01.013

Cited by 100 publications

(124 citation statements)

References 34 publications

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Section: Discussionmentioning

confidence: 99%

“…For the remaining focal animals, 5-pregnan-3-ol-20-on concentrations were expressed as µg/g dried faeces and plotted against time (weeks) for each pZP-treated cow. Baseline values of 5-pregnan-3-ol-20-on concentrations were ascertained for each female using an iterative process as described by Brown et al [45,46]. The average was subsequently recalculated and the elimination process was repeated until there were no values greater than the mean plus 2 standard deviations (SD).…”

Section: Discussionmentioning

confidence: 99%

“…Females were categorized as having an irregular cycle when overall cycle length exceeded or fell short of the reported norm of 13 to 17 weeks [10,[17][18][19][20][21][22][23][24][25]. The non-cycling category was reserved for females who had no identifiable pattern in 5-pregnan-3-ol-20-on concentrations throughout the study period [46].Due to small sample sizes, irregularly cycling females were combined with non-cycling females for statistical analysis comparing cyclicity status to baseline 5-pregnan-3-ol-20-on levels and age. Individuals were categorized as demonstrating periods of anestrus if they had a follicular phase lasting longer than twice the duration of an average normal follicular phase (≥ 10 weeks) [25,47].…”

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confidence: 99%

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Fecal 20-oxo-pregnane concentrations in free-ranging African elephants (Loxodonta africana) treated with porcine zona pellucida vaccine

et al. 2012

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Fecal 20-oxo-pregnane concentrations in free-ranging African elephants (Loxodonta africana) treated with porcine zona pellucida vaccine

et al. 2012

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“…These female elephants are referred to as "non-cycling" or "flatliners". There are many possible causes of ovarian dysfunction in female elephants, such as nutritional insufficiency, stress, obesity and pathological disorder of the ovary [12,13].…”

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confidence: 99%

Prolactin Secretion and Ovarian Function in Cycling and Non-Cycling African Female Elephants (Loxodonta africana)

Yamamoto

Watanabe

et al. 2010

J. Vet. Med. Sci.

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ABSTRACT. Reproduction of captive elephants in zoos has shown a low fecundity and requires improvement. One of the reasons for low fecundity is ovarian dysfunction in many female elephants. To investigate whether prolactin has a correlation with ovarian function in female elephants, the serum concentrations of prolactin, progesterone and estradiol-17 in four African female elephants (one cycling female and three non-cycling female elephants) were measured. Cyclic patterns of prolactin and estradiol-17 were observed in the cycling female elephant, which tended to be high during the follicular phase and low during the luteal phase. On the other hand, a cyclic pattern of prolactin was not observed in the non-cycling female elephants. One of the three non-cycling females (Mako) had developed breasts and showed significantly higher average levels of prolactin than the other female elephants. These results suggested that high concentrations of circulating estradiol-17 during the follicular phase stimulated prolactin secretion. They also suggested that hyperprolactinemia in Mako was one of the causes of the developed mammary glands and ovarian dysfunction.

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“…However, despite the research reviewed above on the assessment of HPA activity, and despite preliminary work to develop assays for stress-activated proteins in African elephants [Bechert and Southern, 2002], only one laboratory, Janine Brown's, has investigated possible links between stress and reproductive success in zoo elephants. So far, Brown's work has focused on acyclicity only; it has revealed no significant links between this and HPA output (although the highest cortisol levels did seem to occur in noncyclers), but in Africans, acyclicity was linked with elevated prolactin levels that stemmed from super-normal prolactinemia in about one-third of the noncycling population [Brown et al, 2004]. As yet, there seem to have been no studies of the possible role of stress (perhaps acting via prolactin or oxytocin) in the long parturitions, high infant mortality rates, and other reproductive problems common in zoo elephants.…”

Section: Reduced Reproductive Successmentioning

confidence: 99%

How should the psychological well‐being of zoo elephants be objectively investigated?

2010

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Animal welfare (sometimes termed ''well-being'') is about feelings -states such as ''suffering'' or ''contentment'' that we can infer but cannot measure directly. Welfare indices have been developed from two main sources: studies of suffering humans, and of research animals deliberately subjected to challenges known to affect emotional state. We briefly review the resulting indices here, and discuss how well they are understood for elephants, since objective welfare assessment should play a central role in evidence-based elephant management. We cover behavioral and cognitive responses (approach/avoidance; intention, redirected and displacement activities; vigilance/startle; warning signals; cognitive biases, apathy and depression-like changes; stereotypic behavior); physiological responses (sympathetic responses; corticosteroid output -often assayed noninvasively via urine, feces or even hair; other aspects of HPA function, e.g. adrenal hypertrophy); and the potential negative effects of prolonged stress on reproduction (e.g. reduced gametogenesis; low libido; elevated still-birth rates; poor maternal care) and health (e.g. poor wound-healing; enhanced disease rates; shortened lifespans). The best validated, most used welfare indices for elephants are corticosteroid outputs and stereotypic behavior. Indices suggested as valid, partially validated, and/or validated but not yet applied within zoos include: measures of preference/avoidance; displacement movements; vocal/postural signals of affective (emotional) state; startle/vigilance; apathy; salivary and urinary epinephrine; female acyclity; infant mortality rates; skin/foot infections; cardio-vascular disease; and premature adult death. Potentially useful indices that have not yet attracted any validation work in elephants include: operant responding and place preference tests; intention and vacuum movements; fear/ stress pheromone release; cognitive biases; heart rate, pupil dilation and blood pressure; corticosteroid assay from hair, especially tail-hairs (to access endocrine events up to a year ago); adrenal hypertrophy; male infertility; prolactinemia; and immunological changes. Zoo Biol 29:237-255,

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Comparative endocrinology of cycling and non-cycling Asian (Elephas maximus) and African (Loxodonta africana) elephants

Cited by 100 publications

References 34 publications

Fecal 20-oxo-pregnane concentrations in free-ranging African elephants (Loxodonta africana) treated with porcine zona pellucida vaccine

Fecal 20-oxo-pregnane concentrations in free-ranging African elephants (Loxodonta africana) treated with porcine zona pellucida vaccine

Prolactin Secretion and Ovarian Function in Cycling and Non-Cycling African Female Elephants (Loxodonta africana)

How should the psychological well‐being of zoo elephants be objectively investigated?

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