References - with notes
Fayrer-Hosken, R. A., Grobler, D., Van Altena, J. J., Bertschinger, H. J. & Kirkpatrick, J. F. Nature 407, 149 (2000). "Immunocontraceptive vaccines cause the immune system to produce antibodies that prevent fertilization, without the side effects of hormonal contraceptives. ("Female elephants with oestradiol implants have shown aberrant behaviour by separating off within the family unit") "The vaccine antigens are the proteins of the zona pellucida, the clear protein coat surrounding mammalian eggs. The surface structures of the elephant zona pellucida are very similar to those of the pig zona pellucida (pZP)"..."Female zoo elephants vaccinated with pZP and an adjuvant all developed antibodies that persisted for 12-14 months 1,2, at a level equivalent to those found in horses given immunocontraception." Field method:"Elephants were located from a helicopter, and females to be anaesthetized (by aerial darting) were identified as non-pregnant by the presence of a calf smaller than 1 metre high. We then used ultrasound scans to confirm that females were not pregnant, and all nonpregnant animals were bled to obtain prevaccination serum samples. Twenty-one elephants were given an initial vaccination of pZP with adjuvant; 20 controls received a placebo."..."Of the ten elephants, two (20%) were pregnant after 10 months. This was significantly ([chi]2, P=0.001) lower than the conception rate of the control elephants (89%, 16/18) and initial immunocontraception rates (44%, 8/18)."..."Female elephants with oestradiol implants have shown aberrant behaviour by separating off within the family unit (D.G., personal observation). GPS-collar location data indicated that there was no abnormal separation of the vaccinated females within a family unit over 8 months. This, combined with field observations of vaccinated females, suggests that the immunocontraceptive vaccine causes no behavioural abnormalities.".."Finally, we tested the reversibility of immunocontraception, and its application for a second consecutive year. Of seven elephants from the group that had initially received immunocontraception, four were vaccinated with pZP and adjuvant, and three were not. Twelve months later, the seven elephants were captured and re-evaluated. Ultrasound scans showed that all three untreated females had conceived again, compared with none of the vaccinated elephants, although all were cycling. This indicates that the vaccine is reversible, and that it has no deleterious effect on the ovary and its cyclicity."
Pimm SL. van Aarde RJ. African elephants and contraception. Nature. 411(6839):766, 2001 Jun 14. UI: 11459047 (my summary) When African elephants are protected but confined in a relatively limited land mass, there can be doubling of the population in 10 years- with destruction of the habitat. To preserve that habitat, animals are often culled, and this letter discusses an article in which a vaccination strategy was used to effect contraception instead of allowing the population to increase. Criticisms of the article include the opinion that the control group's cow pregnancy rate semed unrealistically high (89% within a year), and that -by contrast- exagerated the effectiveness of immunocontraception.Their data:"Data from 813 adult cows culled in Kruger National Park between 1979 and 1994 showed that 51% (range, 36-77%) were pregnant." Criticism of cost also made.
Gould KG. Johnson-Ward J. Use of intrauterine devices (IUDs) for contraception in the common chimpanzee (Pan troglodytes).Journal of Medical Primatology. 29(2):63-9, 2000 Apr. UI: 10950453 Experience with one colony, showed "could be done", lots of management issues
Mohle U. Heistermann M. Einspanier A. Hodges JK. Efficacy and effects of short- and medium-term contraception in the common marmoset (Callithrix jacchus) using melengestrol acetate implants. [Journal Article] Journal of Medical Primatology. 28(1):36-47, 1999 Feb. UI: 10372539