Last Updated on February 25, 2022 by Allison Price
Mother Nature doesn’t favor the birth of equine-to-equine twins. A significant percentage of twin embryos die within six weeks. According to the University of California Davis Center for Equine Health, approximately 80% of twins that are present after 40 days of gestation will eventually abort. This is most common after the eighth month of gestation. The mare may experience severe complications such as trauma, illness, inflammation, and founder if she has a late-term abortion. This can lead to reduced fertility and increased risk of developing another foal. The mare may have one or more live foals. In these rare cases, the mare will experience increased foaling problems and a greater loss of foal life. The twins’ combined birth weight equals one foal normal in size and weight.
Horse owners should try to remove the twin embryos as soon as possible, since the odds are so stacked against twin pregnancy. This maximizes the chance of the mare having a healthy, single pregnancy.