Have a bunch of 20 British Blue x steers, 9 months old. Been out at grass about 6 weeks. In last two week I have had about 7 with foul in foot and hence lame. Clears up with a dose of Ultrapen but has taken two shots for a couple. Same fields etc as normal and very occasionally get the odd one but can't work out what is causing it. Have possibly been feeding a bit more supplementary concentrate than usual and grass is longer. Any suggestions or advice please?!