I have no idea, my dad does the spraying, but the spray he uses kills pattersons curse, mustard weed, dandelions, etc.
I think id rather let my horses eat the weeds, then worry about them ingesting chemicals from the weed killer.
?? Weed sprays have a time specified before you can put stock in the paddock - We always leave a few days on top of that - There is no trace of the chemicals in the paddock when they go back in, only good pasture and no weeds.
They will come back year after year, and spread so fast its almost impossible to get rid of them.
This is what spraying stops :] Our paddocks look 10X better than they did before we started spraying - hardly any weeds and a good amount of varied healthy pasture.
I think it seems that dandelion is not okay in excess....but that in moderation it's fine....just like some things that we eat are good for us in moderation, but could make us sick if we ate too much as well...makes sense.
I don't think it's the dandelions themselves - Apparently it is a bacteria/toxin that grows on/in the plant - So if the plants don't have this toxin growing then they are harmless, but if they do, then I would guess any amount could do the damage.
Personally, not a chance I choose to take.