Removing the horse from the offending grass will rectify grass Allergies. Ask your veterinarian, but hay is a substitute that usually won't bother a horse with this problem.
Yes, as long as the conditions are alright i.e. not frosty or icy
If the grass it is on is rich, if it is getting to much sugarbeet or if it gets excited (at a show,hunting etc)
Carpet grass is invasive and most people don't like the look of carpet grass. It takes a long time to grow carpet grass in the spring and carpet grass turns brown quickly when the weather gets cold.
No they don't, as it gets colder you have a winter blanket. And your horse should also have a spring blanket as well.
Early spring most likely. I don't recommend doing so in the winter, it can get cold and blizzard-y.
Yes, it is certainly possible. My brother used to have terrible allergies as a child. Now that he is an adult, he rarely gets allergies to anything.
allergies to water
COWS eat grass and gets eaten by a human a hamburger
a div gets a horse which is rethared and it gets blowen up
Grass gets water by us and dew
The sun.
Grass uses most of the energy it gets from sunlight for its own life processes.