Hello Ryan, while I am not a dairy farmer, a few details might help in your getting answers. Are you intending buying in the UK and exporting to Romania? have you looked into the import/export protcols involved in doing so? What is the market for the milk - fresh milk sales or processing eg: for cheese production, this will have a bearing on breed choice, as will production system, milking from grass or intensive feeding?
For sheer volume from concentrated feeds, Holstein is the choice, high solids (cream) Channel island breeds such as Jersey and Gurnsey are good choices, milking from a predominantly grass forage system will give a choice of breeds such as Shorthorn and Danish Reds, but they need to be sourced from herds already milking on a grass forage system.
I hopr this helps, your answers might solicit more information from more knowledgeable sources.