Study into common cause of abortion in thoroughbred breeding

Researchers at the Royal Veterinary College (RVC) have been awarded funding to build on their studies into umbilical cord torsion (UCT) in thoroughbreds. This research, funded by the Alborada Trust, continues the first ever comprehensive study of UCT in the world, looking at possible causes and, the development of novel diagnostic tools that will help vets to detect and monitor the condition.

Sadly, one in 25 UK thoroughbred pregnancies result in pregnancy loss during mid to late gestation – a figure that has shown no significant improvement over the last 30 years. This loss is caused by excessive twisting of the umbilical cord, which leads to blockage of the blood supply and the subsequent death of the foetus.

Across the globe, with the exception of Australia, the proportion of pregnancy loss attributed to UCT is significantly lower. This is most noticeable compared to North America, with UK occurrences 10 times higher than in the USA. The reason why certain pregnancies result in long or excessively twisted umbilical cords, and for this dramatic geographic variation in occurrence, is poorly understood.

Researchers at the RVC are leading a collaboration with colleagues at Cornell University, Rossdales Laboratories and, Hagyard Equine Medical Institute to explore the reason why the umbilical cord twists excessively mid-pregnancy. Together, they hope to establish new ways of detecting the twisting prior to the pregnancy being aborted.

The RVC-led team is driving for an international consensus on UCT.  They will use epidemiological modelling to refine and update the current diagnostic criteria for UCT, allowing for more reliable comparisons between populations within the UK and overseas. This would make it easier for vets to accurately diagnose the condition – no matter which country they are in and, would help identify risk factors and to optimise the management of pregnant mares.

The researchers will also characterise subcomponents and key proteins in both normal and diseased umbilical cords, to identify any potential regions that could be monitored clinically. These areas could then be examined using ultrasonography in mid-gestation to assess the diagnostic potential for mares that are at risk of UCT abortion.

The development of novel diagnostic tools will also enable vets to predict mares at risk of suffering a UCT pregnancy loss and, monitor the efficacy of treatment for the condition. Ultimately, the findings from this project will improve the understanding of this cause of equine pregnancy loss, and abortion.

Jessica Roach, Research Fellow at the RVC, said:

“The generous funding from The Alborada Trust will allow us to build on our understanding of umbilical cord torsion. This project brings together researchers who are leading their field and I hope that this will allow us to forward our understanding of this condition. Our aim is to develop novel diagnostic tools to identify pregnancies with a torsed umbilical cord and ultimately, prevent or decrease the risk of pregnancy loss.”

For more information on the study, please visit: https://www.rvc.ac.uk/research/projects/investigation-of-clinical-predictors-of-equine-umbilical-cord-torsion-and-abortion