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Contraception in Wildlife

captive breeding in namibia is not allowed
Captive breeding in Namibia is not allowed.
DR Henk Bertschinger reproductive specialist
Dr Henk Bertschinger Reproductive Specialist.

The ideal contraceptive for wildlife should have no side effects. It should be safe, also in pregnant females, have minimal effects on behaviour, should not pass through the food chain, be affordable and delivery should be easy – ideally allow remote delivery. In many cases a reversible method is preferable to permanent methods so that animals can breed again at a later stage.

ideal contraceptive should have no side effects
Ideal contraceptive for wildlife should have no side effects.
contraception programme started 1998
@ AfriCat the cheetah and leopard contraception programme started in 1998 with Prof Bertschinger.

The older method of contraception in carnivores was a hormonal implant, using a hormone similar to the one used in human anti-baby pills or depot preparations. In carnivores a synthetic long acting silicone implant was used which inhibited the oestrous cycle in females. The side effects of the older contraceptive are cancer of the mammary glands, uterus and liver, uterine infections, obesity and male-like behaviour after extended periods of use.

 

The modern wildlife contraceptive methods are: immunocontraception using either the porcine zona pellucida vaccine (successful in elephants) or GnRH vaccines (used to control aggression in elephant bulls, boar taint in male piglets, oestrous cycle of horses and many others) and hormonal contraception using a GnRH agonist implant.

testicles measured
The testicles are measured as some contraceptive measures can cause them to shrink.
ultrasound on screen
This is what an ultrasound looks like on screen. If the cat was pregnant the embryos would be seen.

At AfriCat the cheetah and leopard contraception programme started in 1998. We were fortunate enough to get hold of a new contraceptive developed in Australia, called deslorelin (GnRH agonist). Deslorelin is a gonadotropin releasing hormone which is very similar to the body's own gonadotropin releasing hormone (GnRH), which is secreted by the brain. Normally GnRH stimulates the pituitary gland to secrete two hormones - follicle stimulating hormone (FSH) and luteinizing hormone (LH) both of which control the development of follicles, which contain eggs and then bring about ovulation in the ovary. In the male they would act on the testicle where they would stimulate the production of testosterone and sperm. So if we could stop the secretion of FSH and LH we would have the ideal contraceptive for both sexes. Deslorelin in the form of the long-acting implant Suprelorin (Virbac Animal Health, Australia) is precisely such a contraceptive. The implant, a small pellet, is injected subcutaneously on the side of the neck. For cheetahs we use a 4.7mg implant which lasts approximately 18 months. In lions we use double the dose and this lasts about 30 months until females conceive again. In cheetahs it works in both females and males. In males as spermatogenesis is an ongoing process and it takes 6-8 weeks for sperm to become nonviable. In females the effect is almost immediate. Deslorelin can be used in baboon, monkeys, mandrills, wild dogs, leopards, tigers and a number of other species. It does not work so well in larger animal like elephants where instead we make use of a contraceptive vaccine.

Deslorelin is self-reversing, in that after 18-24 months there is insufficient hormone released to suppress the release of the two gonadotropin hormones. And so, slowly the animal will start cycling again. The first few cycles of a female will be infertile. The recovery in the male will be slow as well. Testosterone recovery is more rapid than the production of sperm which will take months to recover. If we want to maintain contraception in male and female cheetahs we treat them annually during the annual health check. If on the other hand a cat is released into the wild and we want her/him to breed we simply stop treating and allow the implants to reverse.

contraception diagram

Figure 1: How the deslorelin implant works to suppress reproduction in cheetahs.

 

Group behaviour doesn't seem to have changed over the year although males are less aggressive. In cases of aggressive or over-dominant males we can double the dose of the implant which helps reduce aggression. Most coalitions are siblings although unrelated cheetahs can be habituated to form a group - this is beneficial as it means fewer camps are needed and therefore the cats can have a bigger area to share.

Written by first year vet student and AfriCat volunteer: Ayla Newmarch
Information supplied by Professor Henk Bertschinger.

 

The annual health examinations of the cheetahs at AfriCat give invited specialist veterinarians the opportunity to conduct research on various aspects of animal health, particularly those relating to the health of large carnivores in captivity. As well as providing expert information on the health of AfriCat’s animals, the examinations also allow for the comparison of results with similar studies being conducted on large carnivores in other captive facilities. Some of this information can also be used to gain insight into the health of large carnivores in the wild.

 

Read more about the work of Prof Bertschinger:

  • Reversible, safe contraception in captive felids at AfriCat. (download PDF)
  • Deslorelin Reproduction Supplement (Induction of contraception in some African wild carnivores by downregulation of LH and FSH secretion using the GnRH analogue deslorelin). (download PDF
  • Control of reproduction and sex related behavior in exotic, wild carnivores with the GnRH analogue deslorelin. (download PDF
  • Detection of feline CORONAVIRUS infection in southern African nondomestic felids (download PDF

 

wildlife contraceptive methods are immunocontraception
Wildlife contraceptive methods are immunocontraception.
porcine zona pellucida vaccine
Using either the porcine zona pellucida vaccine.
hormonal contraception gnrh agonist implant
Or a hormonal contraception using a GnRH agonist implant.
implant injected subcutaneously on the side of the neck
The implant, a small pellet, is injected subcutaneously on the side of the neck.
cheetah females have a gestation period of 93 days
Cheetah females have a gestation period of 93 days.
ovulation in cheetahs is induced
Ovulation in cheetahs is induced which means that, like other cats, they must be mated repeatedly for ovulation to take place.
cheetah males have little spikes on their penis
This is the reason why cheetah males have little spikes on the penis which stimulate the vagina during mating.
best semen quality produce most cubs
The male with the best semen quality will produce the most cubs.
Dr Henk working on cheetahs 35years
Dr Henk Bertschinger has been working on cheetahs now for about 35 years. His studies have shown that 40% of both captive and wild males have good semen quality, 30% have fair quality semen and the remaining 30% have very poor semen quality.
double dose implant helps reduce aggression
In cases of aggressive or over-dominant males we can double the dose of the implant which helps reduce aggression.

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