In July 2017, we saw the first successful aspiration of an oocyte on a sedated white rhino. This is one of the first goals achieved towards successfully producing rhinoceros offspring through in vitro fertilisation (IVF).
Dr Morné de la Rey of Embryo Plus explains that this is part of a project to succeed with IVF reproduction in white rhinoceros. The main goal is to save the northern white rhino (NWR). “There are only three northern white rhinos left in the world. If we succeed with IVF in rhino, we might have a chance of saving the species.”
Assisted reproductive technology (ART), of which IVF is one example, has taken significant strides in changing the way successful operators in the cattle, sheep and goat livestock industry preserve, trade with, improve and proliferate their genetic stock. “The way breeding of endangered species is taking its course facilitates a natural progression towards using assisted techniques to enhance the multiplication and preservation of wildlife in the future.”
According to Dr De la Rey, ART has various levels and can be used to a lesser or greater extent. “The basic form is the use of semen from a ram or bull for artificial insemination (AI). Then there is embryo transfer (ET) and in vitro fertilisation (IVF) to utilise female genetics, and lastly nuclear transfer (NT), also known as cloning.”
IVF for rhino conservation
IVF is a complex technique that holds a lot of potential for use in wildlife conservation. Oocytes (egg cells) are collected (aspirated) by using a needle to enter the ovaries of the female animal to extract the oocytes. These oocytes are taken to a laboratory where collected semen is used to fertilise them. The resulting embryos are incubated for six to eight days in a culture medium inside an incubator. After the growth period, the embryos are transferred into the uterus of a suitable, fertile surrogate.
How will this process be used to save the NWR? Dr De la Rey explains that, to be able to save the NWR, embryos will have to be transferred into southern white rhinos (SWR). “To produce viable NWR offspring at this stage would require a combined effort from various groups around the world. The bull Sudan, one of the last three NWR, is sub-fertile at his old age, and therefore semen should be used from the frozen semen banks around the world.
“Possible oocyte collection from the two remaining females should be one way forward to produce IVF embryos. Using the SWR as surrogates are obvious and the only remaining option. There are relatively many SWR remaining in South Africa – several in private ownership – and a number of willing farmers to participate in such a venture. A collaboration with South African farmers must also form part of the strategy and is quite possible.”
Dr De la Rey says successful IVF in rhinoceros will not only help the NWR. “We will also be able to help white and black rhinos to shorten their inter-calving period. This will be especially beneficial where some animals show uterine or ovarian problems.
“Successful IVF in other species will see a general improvement in the breeding of endangered animals. Remember, better populated and related species can be used as surrogates. There is the case where a bongo embryo was carried by an eland, which gave birth to a healthy bongo calf. We have also been repeatedly successful in producing western Zambian sable embryo calves born from southern sable surrogates.”
Pumelelo, the first African buffalo calf conceived through in vitro fertilisation, was born on 28 June 2016 on Frans Stapelberg’s Lekkerleef Buffalo Ranch, near Marble Hall in Limpopo. “This marked the first time the species has ever been reproduced through IVF. This breakthrough is of great significance as it is the first of its kind in the world, and holds great promise for the continued survival of endangered species,” says Dr De la Rey.
The practical execution is more complex and slower in wildlife than in domestic animals, but will undoubtedly be of great benefit. “Remember, every one or two extra animals bred give the offspring a chance to breed normally.” – Marike Brits, Stockfarm
For more information, contact Dr Morné de la Rey on 012 250 2359 or email@example.com.