Resumo

BERTSCHINGER, Hendrik J.  e  LUEDERS, Imke. Use of anti-gonadotropin-releasing hormone vaccines in African elephants (Loxodonta africana): A review. Bothalia (Online) [online]. 2018, vol.48, n.2, pp.1-9. ISSN 2311-9284.  http://dx.doi.org/10.4102/abc.v48i2.2320.

BACKGROUND: Androgen-related aggressive behaviour and musth cause serious problems in captive African elephant bulls and often lead to human and animal injuries, and damage to property. OBJECTIVES: To review the work carried out with anti-gonadotropin-releasing hormone (GnRH) vaccines to control androgen-related behaviour and fertility in captive and free-ranging elephant bulls and the induction of anoestrus in elephant cows. METHOD: In the first study, an anti-GnRH vaccine from Pepscan was tested in six bulls (four captive and two free-ranging). Once the vaccine Improvac^® became available, the effect on behaviour, the reproductive organs and semen quality was tested. Improvac^® was also used to attempt induction of anoestrus in elephant cows. RESULTS: The first study proved that aggressive behaviours are significantly associated with increased faecal androgen concentrations. Musth (n = 1) and aggressive behaviour (n = 2) were down regulated and correlated with a decline in faecal androgen concentrations. Aggression and musth could be controlled with Improvac^® (600 µg), but were more consistent when the dose was increased to 1000 µg administered every five to six months. The same dose down regulated testicular function and bulls (n = 17) were rendered infertile within 12 months after commencement of treatment. Initial attempts to induce anoestrous with 600 µg in free-ranging elephant cows gave inconclusive results, but 1000 µg in captive cows delivered five-monthly was successful. CONCLUSION: The treatment of elephant bulls with Improvac^® resulted in the successful down-regulation of androgen-related behaviour and sperm production in captive and wild elephant bulls of various ages (≤ 34 years). Preliminary studies to induce anoestrus in cows with Improvac^® appear to be successful.

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