A new rule has been introduced, with immediate effect, preventing Horses or Ponies with Invalid JMB certificates from competing in affiliated classes of the JMB Stakeholders. 

Rule 39a states 

Once a JMB height certificate has been invalidated that horse or pony must be either
i) be re-measured (at the discretion of the Board) before it competes in any further affiliated classes of the JMB Stakeholders; or
ii) be measured again before it competes in any further affiliated classes of the JMB Stakeholders

The reason for the invalidation will dictate whether a remeasurement or a measurement must take place.

Click HERE for the current rules