The long term objective to breed ostriches according to scientific principles and to provide expertise to the local industry on the subject has been given a boost thanks to research by Dr Marna Smith. She has established a protocol by which to cool ostrich semen successfully for up to two days, or to store it indefinitely after freezing until it is required for the artificial insemination of female birds.
Dr Smith received her doctorate in Animal Sciences on the subject from Stellenbosch University (SU) in March. She completed a large part of her research at the Oudtshoorn experimental farm of the Western Cape Department of Agriculture. The research by this resident of Bot River in the Overberg forms part of a larger project on scientific ostrich breeding methods. Researchers of the Western Cape Department of Agriculture and students and staff of SU are involved in these efforts.
Further refining of the protocol will lead to better assisted reproduction (AR) techniques. This should make it possible for private breeders to breed ostriches more specifically so that certain genetic superiority for traits of economic importance can be transmitted from generation to generation. If successfully implemented in future, stored semen from elite birds of outstanding genetic merit can thus be bought in from other studs to be used to fertilise eggs produced by female birds.
The long term preservation of ostrich semen makes it possible to artificially inseminate females with frozen semen during their most important reproductive months. Such samples should preferably be collected during periods when semen production is at its best. These cycles do not always overlap in nature.
"Better preservation methods of semen will make it possible to build up ostrich studs with pedigree information," Dr Smith explains.
Ostriches living in flocks make use of communal nests, which makes the assignment of pedigrees difficult, if not near impossible.
"Genetic tests to assign pedigrees to chicks produced by free ranging ostriches are available, but are not currently affordably for the wider industry," explains her study leader, Prof Schalk Cloete, extraordinary professor in the SU Department of Animal Sciences, and a member of the Western Cape Department of Agriculture research team.
Dr Smith's research will, along with other studies, lead to an executable protocol for the AR of ostriches. This means that farms and studs will eventually be able to keep fewer male breeding birds.
"Fewer males or no males mean considerably lower costs and a higher profit margin for farmers," Dr Smith explains the advantages of AR programmes. "You also have to cope with fewer aggressive male birds, which make things safer for farm workers. Such advantages are already the norm in the dairy industry."
The technology also makes it feasible to establish a biobank where semen from ostriches with good genetic traits can be stored in the long term. It is not only important for the storage of seminal plasma of genetically superior animals, but can also be indispensable when colonies must be built up again following a disease like bird flu, during which affected animals have to be destroyed.
"After such a disease has run its course, one can use a biobank with good genetic material to re-establish a flock with the same genetic value," says Prof Cloete.
Dr Smith among other things developed the first ostrich-specific diluent for semen. She established the conditions under which ostrich semen can be cooled to 5 degrees Celsius and stored for up to 48 hours while it is transported to farms, for instance. She also established how to freeze ostrich semen for indefinite periods in liquid nitrogen, in the presence of a cryo-protectant.
"There was no difference in the fertility of eggs laid by females inseminated with cooled or frozen semen, compared to those inseminated with fresh, untreated semen," adds Dr Smith.
Some of her research findings have already been published in a number of scientific journals. In a paper in Animal Reproduction Science earlier this year, she detailed the characteristics needed to classify ostrich semen.
"These characteristics enable breeders to evaluate the potential fertility of the semen of male ostriches, and how suitable each would be for storage to be used in a more intensive breeding programme in future," Dr Smith explains.
She proposes that this evaluation should take place in the spring and early summer, when male ostriches experience a peak in semen production.
For further reference, read:
Smith, A.M.J. et al (2016). Classification of ostrich sperm characteristics, Animal Reproduction Science 168, 138-150.
Photo caption: Dr Marna Smith at work in the laboratory during the course of her research. Photo: Gareth Wiese
For media enquiries only:
Prof Schalk Cloete
Extraordinary professor in the Department of Animal Sciences, Stellenbosch University
Researcher of the Western Cape Department of Agriculture
021 808 5230
Dr Marna Smith
021 865 2053