Sport Ireland, which is the statutory body with responsibility for the development of sport in Ireland, provides advice and guidance as required to all National Governing Bodies (NGBs), in relation to specific queries of the type indicated in the Deputy's question.
I understand that there has been communication with the NGB concerned, Horse Sport Ireland, to the effect that horse riding lessons for children can be classed as underage non-contact training on the basis of compliance with the following guidance issued by HSI: https://www.horsesportireland.ie/permitted-sport-horse-activity-in-the-context-of-covid-19-level-5-updated-23-april-2021/