As a keeper of horses, ponies, donkeys and zebras (equidae) you must submit a notification and registration of all kept equidae in the Identification & Registration System (I&R) of RVO (Rijksdienst voor Ondernemend Nederland). This applies from 21 April 2021. As of today it is possible to link horses to your UBN.
On 21 April 2021 the European Animal Health Regulation will come into force in the Netherlands and with it the requirements related to the identification and registration (I&R) of equidae will be much stricter. In practice, as of 21 April, there will be a registration requirement for both hobby and professional horses, enabling the government to have insight into the number of horses per location. This information is important in order to have a better overview of where all equidae are located in the Netherlands in the event of an outbreak of a contagious disease such as African Horse Sickness.