Potential of a gonadotropin-releasing hormone vaccine to suppress musth in captive male Asian elephants (Elephas maximus)

Somgird, Chaleamchat; Homkong, Pongpon; Sripiboon, Supaphen; Brown, Janine L.; Stout, T.A.E.; Colenbrander, B.; Mahasawangkul, Sittidet; Thitaram, Chatchote

doi:10.1016/j.anireprosci.2015.11.019

Cited by 18 publications

(17 citation statements)

References 46 publications

(75 reference statements)

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“…Another contraceptive approach involves GnRH vaccines to produce antibodies that block binding of endogenous GnRH to gonadotropin receptors in the pituitary gland, which in turn inhibits release of FSH and LH. Various vaccines have been used in domestic and wild elephants for contraceptive and aggression‐related behavioural control, both in males and females (De Nys et al ., ; Somgird et al ., ). Continued trials in the USA utilize commercial GnRH vaccines, Bopriva ® (Zoetis) and Improvest ® (Pfizer Animal Health) to suppress ovarian activity, boosting at monthly intervals for lasting effectiveness.…”

Section: Reproductionmentioning

confidence: 97%

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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Section: Reproductionmentioning

confidence: 97%

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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“…Antibody titres were shown to rise after two to three injections in adult Asian elephant males (Somgird, Homkong et al ., ). However, they remained elevated for only 2 months.…”

Section: Gnrh Vaccine Application In Elephantsmentioning

confidence: 97%

“…However, the commercial GnRH vaccines have not been tested in this respect, especially following multiple treatments for several years. In a study on Asian elephant bulls with monthly injections for three consecutive months, testosterone levels were back to initial levels c. 5 months after the last injection (Somgird, Homkong et al, 2016). Similarly, in African elephant bulls with four injections at 3-7-week intervals, testosterone was back to normal or bulls entered musth 6 months after the last booster (De Nys et al, 2010).…”

Section: Reversibilitymentioning

confidence: 99%

“…Injection with exogenous GnRH induces a surge of LH secretion, followed by the release of testosterone (Somgird, Sripiboon et al, 2016) Thus, it is not surprising that immunization against GnRH led to lowered testosterone and to cessation of musth in elephants in the available studies (De Nys et al, 2010;Rajapaksa et al, 2010;Lueders et al, 2014Lueders et al, , 2017Somgird, Homkong et al, 2016). The effect of the GnRH vaccine on blood serum (Somgird, Homkong et al, 2016) or faecal androgen (Lueders et al, 2017) levels was measured. Results suggest that an initial inoculation followed by a booster 4-6 weeks later with a minimum of 600-1000 lg of GnRH conjugate was enough to suppress testosterone levels for at least 5 months.…”

Section: Gnrh Vaccine Use In Male Elephantsmentioning

confidence: 99%

“…However, they remained elevated for only 2 months. Monthly boosters were therefore given in several studies at least at the beginning of the treatment (Rajapaksa et al, 2010;Lueders et al, 2014;Somgird, Homkong et al, 2016). One study in an Asian elephant female showed that a titre rise was only evoked after an adequate GnRH protein-conjugate dose of 12Á5-30 mg (Repro-BLOC ® ) (Boedeker et al, 2012).…”

Section: Gnrh Antibody Titre Developmentmentioning

confidence: 99%

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Use of gonadotrophin releasing hormone (GnRH) vaccines for behavioural and reproductive control in managed Asian elephantElephas maximusand African elephantLoxodonta africanapopulations

Oerke

Knauf-Witzens²,

Young

et al. 2019

International Zoo Yearbook

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Because of their size and reproductive anatomy, surgical castration is not a practical option in adult elephants. However, similar to other species in human care, the effects of gonadectomy are desired in specific situations. This may be for contraceptive purposes, or for behavioural or veterinary management of elephants in human care or wild elephants managed in small reserves. Research into non‐surgical contraceptive measures for wild and domestic animals has resulted in an array of hormonal and immunological options to downregulate gonadal function. Driven by the production‐animal industry, commercial gonadotrophin releasing hormone (GnRH) vaccines are readily and cheaply available. This immunocontraceptive is effective in both males and females as it inhibits gonadotrophic hormone release and, thus, downstream stimulation of testicles and ovaries. Here, available studies from the past 10 years on the GnRH vaccine application in male and female elephants are reviewed. Furthermore, we add our own experience gathered from the treatment of male African elephants Loxodonta africana and female Asian elephants Elephas maximus in human care. The GnRH vaccine offers a viable approach for various management purposes. It should be noted that the GnRH vaccine was not primarily designed as a reversible contraceptive. Therefore, its use must be well justified on an individual basis and the effects closely monitored.

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Parasite‐associated mortality in a long‐lived mammal: Variation with host age, sex, and reproduction

Lynsdale

Mumby

Hayward

et al. 2017

Ecology and Evolution

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Parasites can cause severe host morbidity and threaten survival. As parasites are generally aggregated within certain host demographics, they are likely to affect a small proportion of the entire population, with specific hosts being at particular risk. However, little is known as to whether increased host mortality from parasitic causes is experienced by specific host demographics. Outside of theoretical studies, there is a paucity of literature concerning dynamics of parasite‐associated host mortality. Empirical evidence mainly focuses on short‐lived hosts or model systems, with data lacking from long‐lived wild or semi‐wild vertebrate populations. We investigated parasite‐associated mortality utilizing a multigenerational database of mortality, health, and reproductive data for over 4,000 semi‐captive timber elephants (Elephas maximus), with known causes of death for mortality events. We determined variation in mortality according to a number of host traits that are commonly associated with variation in parasitism within mammals: age, sex, and reproductive investment in females. We found that potentially parasite‐associated mortality varied significantly across elephant ages, with individuals at extremes of lifespan (young and old) at highest risk. Mortality probability was significantly higher for males across all ages. Female reproducers experienced a lower probability of potentially parasite‐associated mortality than females who did not reproduce at any investigated time frame. Our results demonstrate increased potentially parasite‐associated mortality within particular demographic groups. These groups (males, juveniles, elderly adults) have been identified in other studies as susceptible to parasitism, stressing the need for further work investigating links between infection and mortality. Furthermore, we show variation between reproductive and non‐reproductive females, with mothers being less at risk of potentially parasite mortality than nonreproducers.

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Potential of a gonadotropin-releasing hormone vaccine to suppress musth in captive male Asian elephants (Elephas maximus)

Cited by 18 publications

References 46 publications

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

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

Use of gonadotrophin releasing hormone (GnRH) vaccines for behavioural and reproductive control in managed Asian elephantElephas maximusand African elephantLoxodonta africanapopulations

Parasite‐associated mortality in a long‐lived mammal: Variation with host age, sex, and reproduction

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