We have had this problem as well this year, we realized it was certainly stemming from the pastures. As spring is coming in, we have had a ton of rain here and the grass came up super green and super fast. Not thinking we let out herd out to graze and a couple days later several had bloat. Turns out that because of the weather lately the grass came in and all of the sugars we at the top of the grass so being winter the goats rumen hadn't been exposed to this sugar in a while, causeing an imbalance. So we had to slowling 'ween' them back onto the grass instead of a free for all. also if bloat does occur still there is a little concoction online called 'frothy goat bloat' works wonders. Give them that and massage their rumen a little. And burps/gas are a good signSeveral of my boar goats are getting bloat. I can't pat it down and have treated with corn oil and baking soda drench. Also administered 20cc cd anti toxin. But no luck. I haven't changed feed but they have been on pasture that is lush and green.