Greyhounds are hung or decapitated in Ireland if they don´t reach the top 5 in dog races, this has

Lately I read about the greyhounds that are killed in Ireland if they don´t reach the top 5 in dog races anymore, the owners either hang them on trees or even decapitate them if they were former champions, so no one can identify them anymore and also not find the former owner anymore, this is an inhumane cruelty that has to stop, once I even saw a docu about this cruelty on TV...