UP’s Faculty of Veterinary Science and Hemmersbach Rhino Force achieve SA’s first successful equine pregnancies with in vitro-derived embryos

PRETORIA - In a significant joint research effort, the University of Pretoria’s (UP) Section of Reproduction in the Department of Production Animal Studies, together with the Cryovault section of Hemmersbach Rhino Force, have successfully achieved South Africa’s first pregnancies in horses using intracytoplasmic sperm injection (ICSI), followed by the transfer of frozen embryos.

In vitro embryo production in cattle, for which the ICSI procedure isn’t required, has been commercially available in South Africa for the past decade. The first ICSI-derived equine embryos and foal were reported in 1996, and since then, relatively few laboratories around the world have carried out successful procedures.

“In South Africa, the options for horse breeders were limited to artificial insemination or embryo transfer, where the uterus of a donor mare was flushed and the embryo transferred into a synchronised recipient mare,” says Dr Janine Meuffels-Barkas, Extraordinary Lecturer at UP and Rhino Force veterinarian. “The research team is proud to bring the specialised ICSI procedure to South Africa.” 

Over the course of 2025, following training and advice from veterinarians from Belgium’s Ghent University, the team of clinicians and embryologists regularly performed ovum pick-up procedures in mares to retrieve oocytes. Additionally, oocytes were harvested from euthanased mares postmortem. After transport to the Section’s In Vitro Fertilization Laboratory at the Faculty of Veterinary Science, Onderstepoort, the oocytes underwent in vitro maturation, followed by ICSI with frozen-thawed sperm to produce blastocyst-stage embryos.

In November, five embryos were transferred into recipient mares, resulting in three pregnancies, all viable at approximately six weeks of gestation (12 December 2025); these will hopefully produce live foals in October 2026. “This achievement is a significant advance in veterinary medicine in South Africa, aligning equine-assisted reproductive technologies with international standards,” says Prof Martin Schulman, Head of the Section of Reproduction at UP’s Faculty of Veterinary Science. 

For horses, ICSI rather than in vitro fertilisation is the method of choice for reliable in vitro production of embryos. It entails injecting a single, selected sperm into a mature oocyte; this requires specialist equipment and the skills of an embryologist. In the horse breeding industry internationally, ICSI has become an invaluable tool to overcome fertility problems in stallions and mares, overcomes challenges of age and sporting schedules and allows for breeding independently of season and oestrous cycle stage. Additionally, the availability of in vitro embryo production allows for breeding from mares and stallions in cases of fatal disease or injury by using sperm and oocytes collected postmortem and preserving and potentially exporting valuable embryos. 

The success of this initiative supports the collaborators’ broader, long-term objective of developing and refining equine-assisted reproductive technologies for use in conservation programs for threatened African rhinoceros species due to the close phylogenetic relationship between the species. 

The research was funded by Hemmersbach Rhino Force and the Faculty of Veterinary Science’s In Vitro Fertilization Laboratory, and conducted by veterinarians Dr Su-Mari Hoogenboezem, Dr Janine Meuffels-Barkas and Dr Maria Melchert; embryologists Jana van Selms and Mario Smuts; and Prof Martin Schulman. It was supported by the laboratory’s Prof Dietmar Holm, and Stefan Bauer and Ute Schramm of Rhino Force.