Thanks for the link, interesting reading. Persons sharing the information horses died of urea poisoning had Vets attending, this was the diagnosis they were given. Not sure if they got necropsies.
I am just sharing the information so you are aware of “possibilities” in use of urea as pasture fertilizer. Husband refuses to use urea here, so we use the Ammonium Sulphate instead. Not causing reactions in horses, and another benefit is that it is not volitile, not evaporating like urea if not rained on quickly. Sometimes you just can’t get an accurate weather prediction from anyplace! Ha ha I ended up spreading grass seed today in surprise snow!
Hope your rains fall as you need them after applying the fertilizers.