I would agree with Sally re amount of milk being given, ours get about 350ml per feed, if any signs of bloat were seen I would immediately look to reduce the amount of milk per feed much further and consider weaning of milk altogether once over 4 weeks old and eating creep. We lost one at 41/2 weeks old to bloat last year, his twin also suffered from bloat too and got weaned, didn't want to risk losing both of them. Some lambs just must be more susceptible, this is the first time we have seen it and have reared a lot of cades.
Powdered ginger is also reputed to help with milder cases of bloat.
Sally I hadn't realised the effect of bicarb! We add a small amount of bicarb to the milk of any lambs that are prone to scour a bit and had found the opposite effect! Perhaps its down to quantity?
We also add live yogurt to lamlac, we did this as routine this year, we made it go further by adding either goats or sheeps milk to a litre of lamlac and keeping it warm for a few hours so that more yogurt was made, about a 1/5 of this was added to each 2L of lamlac made up. The 17 cade lambs we have reared all seem to have done well on it with no hint of any bloat.