Well I'll take my years of in the flesh experience over your PDF file I'm afraid.
I am not closed minded to new things, but honestly I don't think I have ever had pastures without dandelions, so on this occasion I'm not going to rein them in
Oh and further research (a couple of random clicks of my mouse)
With summer upon us we must be mindful of the likely occurrence of Australian Stringhalt (AS) which occurs in horses grazing drier pastures with poorer soil types and weeds.
Horses severely affected with Stringhalt walk with exaggerated flexion of the hind limbs, often contacting the belly and moving forward with a peculiar bunny hopping gait.
Although the condition is usually not life-threatening, recovery tends to be prolonged often between 6 to 18 months. Muscle wastage can be quite severe.
Although it is recommended that horses be removed from the paddocks they had been grazing, care must be taken that they be moved to a safe area free of obstacles or topographic challenges (like steep hills with dams at the bottom).
One weed that has a particular association with cases of AS is a yellow flowered plant known variously as False Dandelion, Flatweed and Catsear. The botanical name is Hypochoeris radicata (H. Radicata).
Also Illinois is a long way from Aussie land