The EU pledged to cut methane emissions by 30% by 2030, but has not implemented policies to make this happen.

To rear fewer cattle in the EU will not help if the EU imports meat instead. That would transfer the cattle's methane emissions to some other country but not eliminate the emissions. To achieve this necessary goal would require either reducing the emissions per unit of meat or milk produced, or reducing the amounts of meat and milk going into products sold in the EU.

The former may perhaps be possible (I don't know) with different breeds of cattle or different feed. But there is not time to develop them, not before 2030. It would have to be done using existing methods.