The use of embryo transfer in horses is a widely discussed topic and also becoming an increasingly common procedure in veterinary medicine. In this article, you will learn exactly what equine embryo transfer is, how it works and what the costs, advantages and disadvantages are.
What is embryo transfer in horses?
Equine embryo transfer works in a similar way to human embryo transfer: There is a donor mare and a recipient mare. The donor mare is covered by a stallion, be it through natural, fresh or frozen semen. The embryo is then transferred to the recipient mare, who carries the foal. It is important that a suitable recipient mare is chosen. Ideally, she should not be older than ten years, be highly fertile and offer sufficient milk production and a good temperament. Preferably, the recipient mare has already produced foals of her own. Her size should also be similar to the donor mare.
The embryo transfer procedure
Before performing an embryo transfer, the cycles of the donor mare and the recipient mare need to be synchronised. To maximise the chance of a successful procedure the embryo must be transferred only a few days apart, regular ultrasound scanning helps to determine the right time. Ideally, the recipient mare ovulates 48 hours after the donor mare. Six to eight days after ovulation, the so-called embryo flushing is carried out. By then the embryo has developed into the vesicle stage (blastocyst) and can be transferred. The developing embryo is inserted into the surrogate mother through the cervix. Often the embryos are checked in the laboratory first, in order to assess whether the quality is sufficient. The mares are usually stabled at the clinic during the process, but are regularly given the opportunity to stretch their legs. After the embryo transfer, they can return home immediately.
Costs of embryo transfer
Expenses vary, of course, but overall it is a cost intensive procedure. The flushing of the embryo usually amounts to about 200-250 Euros and for the transfer another 50-80 Euros should be budgeted. In addition, there are further costs for follicle controls, ultrasound examinations, swab samples, possible synchronisations of the recipient mare, medication or other examinations and treatments. The usual things like covering costs etc. are also incurred.
Advantages and disadvantages of embryo transfer in horses
Use of mares in breeding during their sport career
Mares that are not used for breeding due to illnesses (orthopaedic, resorptions, abortions etc.) can still pass on their genes
Donor mares can “have” more than one foal per year
Mares that are not supposed to have a foal due to their age can still reproduce
- High costs
- Still not very widespread in Germany
- Complex management
- Genetic health of recipient mare not always known