To all trainers and equine veterinarians 

NHA analysis of a locally sourced altrenogest-containing product has revealed trace levels of trendione and trenbolone as impurities within the product. This has been reported previously in international racing jurisdictions. Trendione and trenbolone are anabolic steroids which are forbidden substances and are not allowed to be present in any horse at any time under the NHA Rules of Racing. Significant penalties may apply for the person responsible and the horse involved, including a 365 day suspension from racing should these forbidden substances be detected in a specimen collected from a horse at any time. 

There are no altrenogest-containing products registered specifically for use in horses in South Africa. The NHA veterinary department strongly advises trainers against the use of altrenogest-containing products, including compounded products, or those intended for use in other species. Furthermore, it is recommended that all current altrenogest-containing products be removed from all trainers’ yards. 

Alternative products such as an injectable, short acting progesterone may be used to suppress oestrus in fillies and mares, which use is provided for in the provisions of the Exempted Substances List (Appendix N of the Rules). Trainers are urged to consult with their private veterinarians. 

Any questions or for further clarity on the above, please contact the NHA Veterinary Department at This email address is being protected from spambots. You need JavaScript enabled to view it.