In what is being viewed as a precedent-setting decision, the Swedish Warmblood Association (SWB) has announced that as of March 1, 2025, it will no longer permit registration in its basic studbook of foals produced using OPU/ICSI reproduction techniques.

‘Painful and invasive’

According to the SWB news release, the change is being made in accordance with Sweden’s Animal Welfare Act. OPU (which stand for Ovum Pick Up) is common around the world but prohibited in Sweden because it is considered operative intervention without a clear medical need.

According to the SWB website, OPU is a technique “that allows a mare to produce significantly more eggs than they normally would and potentially increases the number of foals a mare can have, even more than with ET [Embryo Transfer]. OPU can also be done immediately after the death of a mare.

“Several immature eggs are sucked out (harvested) from the mare’s ovaries through an operative (invasive) process. It is performed via the vagina of an anesthetized mare, and epidural anesthesia is a must, as it is painful. The eggs are then allowed to mature in the laboratory before ICSI, embryo development and embryo implantation can take place. With current technology, OPU is not allowed in Sweden precisely because it is a painful and invasive method.”

In ICSI, or Intracytoplasmic Sperm Injection, “the whole process takes place outside the mare in a laboratory environment,” the website says. “The fertilized egg (embryo) is implanted, immediately or later after freezing, in a surrogate mare when it has been established that the embryo is viable.”

‘Ethical compass’

The SWB release goes on to say that the decision is “forward-looking” and applies to offspring produced with the help of OPU/ICSI from the time this decision was published on March 25, 2024. The decision does not apply to foals born in 2024.

“We want to emphasize that horse welfare always weighs more heavily for SWB than the purely commercial interests. We believe that a clear ethical compass in the longer term will be a success factor,” said Per Jansson, SWB’s chairman of the board.

While enforcing breeder compliance could be difficult, the association will reportedly require written confirmation of such when a foal is registered.

The decision does not affect ET (Embryo Transfer).

Read more about different reproduction techniques for horses here.