Deadly forage?

Birdsfoot trefoil is a good pasture legume.
It is high in protein, but unlike most legumes it carries a low risk of "bloat". The protein in fresh legumes can produce a frothy foam trapping gases in an animal's rumen and causing it too bloat up. In the worst case scenario this can crowd out its lungs and cause it to suffocate.
A pasture mix of grasses and legumes helps to prevent this. So does the high tannin content of birdsfoot trefoil, a legume with an odd sounding name--until you see its seeds.