Endocrine correlates of puberty in female Asian elephants (Elephas maximus) at the Pinnawala elephant orphanage, Sri Lanka

Mendis, S; Jayasekera, Niromi K.; Rajapakse, R. C.; Brown, Janine L.

doi:10.1186/s40850-016-0012-8

Cited by 7 publications

(2 citation statements)

References 17 publications

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“…The remaining data were defined as the baseline. In a previous study, serum progesterone concentrations from Asian elephants ranging from 0.94 to 4.71 ng/mL (>3.99 ng/mL) were detected by using the same EIA protocol [ 34 ]. However, the maximum detectable value of EIA in this study was 3.99 ng/mL.…”

Section: Methodsmentioning

confidence: 99%

“…Asian and African elephants are thought to live for more than 70 years [ 31 , 32 ], and most females can continue to reproduce until the age of 60 [ 27 ]. Given these considerations, throughout the long lives of female elephants, the regular monitoring of blood progesterone is an important tool in the strategies and management of breeding in order to (1) monitor gestation to avoid stillbirth and predict the delivery time and ovarian cycle patterns [ 33 ]; (2) avoid unexpected pregnancies around the early puberty period [ 34 ]; (3) determine the optimal time for mating and control the management of females of prime breeding age (before 30 years of age) and old females management [ 8 , 35 ]; (4) diagnose pseudopregnancy by identifying the prolonged duration of the luteal phase [ 34 ], etc. Furthermore, determining whether elephants have a normal ovarian cycling status requires managers to know and calculate the baseline progesterone.…”

Section: Introductionmentioning

confidence: 99%

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Seasonal Effects on Body Condition and Characteristics of the Estrous Cycle in Captive Asian Elephants (Elephas maximus) in Thailand: A Retrospective Study

Yang

Tummaruk

Angkawanish

et al. 2023

Animals

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The aim of this study was to investigate the effects of season on the body condition score (BCS), the characteristics of the estrous cycle (luteal phase [LPL], follicular phase [FPL], estrous cycle [ECL] lengths, and the start of the luteal phase [SLP] and follicular phase [SFP]), and progesterone levels (baseline and peak) of eight captive Asian elephants (Elephas maximus) in Thailand. From 2014 to 2019, blood samples were collected weekly for serum progesterone enzyme immunoassays (EIAs). Estrous cycles (n = 70), including the luteal and follicular phases, and BCS (n = 70) were recorded. Based on the BCS, the LPL, FPL, and ECL were assigned to the following two groups: normal (BCS = 3.0–4.0, n = 38) and overweight (BCS = 4.5–5.0, n = 32). The findings demonstrated that there was no difference in LPL between the groups. However, in the normal group, the ECL was one week longer (14.9 ± 1.7 vs. 13.9 ± 1.7 weeks; p < 0.05), and the FPL also tended to be one week longer (7.2 ± 1.7 vs. 6.4 ± 1.5 weeks; p = 0.06) than in the overweight group. The mean progesterone level during the rainy, hot, and cool seasons was not statistically different. Based on the yearly averaged BCS from three seasons, the baseline and peak levels of progesterone were classified into the normal (n = 16) and overweight (n = 12) groups. Females with a normal BCS tended to exhibit higher progesterone peak levels (p = 0.08). The majority of peaks appeared during the rainy season (53.57%). The BCS was highest during the hot (4.47) and rainy (4.38) seasons, but not during the cool (4.12) season. The LPL, FPL, and ECL were not affected by the season in which the luteal phase occurred. On the other hand, the rainy season had a significant effect on the SFP, resulting in a longer LPL (p < 0.05) and ECL (p = 0.01); both were the longest during the rainy season. In conclusion, the effects of season on BCS may be related to characteristics of the estrous cycle and peak progesterone levels. Ultimately, these findings provide ground knowledge to assist elephant managers and owners in planning breeding activities using seasonal effects and BCS measurements in tropical climates.

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Section: Methodsmentioning

confidence: 99%