A lot of lesser race horses end up being sold abroad. if you go to any of the cheaper sales at Newmarket and Doncaster ther are loads of buyers from Italy,Russia,Kasakstan etc. Doesn't bear thinking about the life they have out there.
One of the horses we sold went to Cheq republic, he was named and then never heard of again,:-( shame as he was a nice looking horse although too big for racing, would have made a great police horse we always said (and the only horse i've ever known to eat shavings like straw!!)
Don't know numbers as there probably aren't any offcial figures for slaughter, only lists of deaths at Weatherby's, but there are 3,000 foals born in Britain and Ireland for the industry each year. How many TB's do you see around??