Reproductive Control of Elephants

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

“…Determination of pregnancy within treated cows was based on luteal phase lengths persisting longer than 3-5 months [21,22]. Occurrence of behavioural estrus was compared with the time of increasing progesterone metabolite concentrations as behavioural estrus has been reported to last from 2 to 6 days [10]. Increases in progestagen concentrations following the end of the follicular phase confirm that ovulation has taken place with the formation of an active corpus luteum [21].…”

“…Currently, various approaches have been explored in regards to managing elephant numbers, all with different advantages and disadvantages, including culling [5,6], translocation [5,7], range expansion [5,7,8], sterilization [9,10] and contraception [10,11]. In this regard, the use of the porcine zona pellucida (pZP) vaccine for immunocontraception of African elephant cows is a fairly recent development.…”

“…After treatment intramuscularly, the vaccine triggers anti-zona pellucida antibodies which bind to the zona pellucida capsule including sperm receptor sites and so prevent fertilization from taking place [1,15]. Since the initial studies, pZP-immunocontraception has been implemented in 7 private game reserves where it has been shown to be 100% effective in over 100 cows treated [10].…”

“…After treatment intramuscularly, the vaccine triggers anti-zona pellucida antibodies which bind to the zona pellucida capsule including sperm receptor sites and so prevent fertilization from taking place [1,15]. Since the initial studies, pZP-immunocontraception has been implemented in 7 private game reserves where it has been shown to be 100% effective in over 100 cows treated [10].Nevertheless, pZP vaccination was not fully embraced primarily due to a lack of knowledge regarding potential adverse changes in behaviour. However, Delsink et al [11,16] found no significant change in core and total range use, matriarchal status, cow/calf interaction, herd fragmentation/isolation, musth occurrence, bull hierarchy, and no aberrant or unusual behaviour witnessed among the herds.…”

“…Phase length estimates as well as ovarian cycle length estimates are given as mean ± SD. 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].…”