It makes no difference if mares and geldings are together when a mare is in heat. A gelding is a castrated horse and he has no sex drive or ability to impregnate a mare. Therefore a gelding would be like just another horse to a mare in heat.
No not very much. My horse is a gelding and one time I was riding him. He eased near a mare without me knowing (because I was somewhere in space) and she kicked him. So they do not get alone very...
The exact answer is going to depend on what area of the world the mare is in.
In the United States, a mare should be current on the vaccines which the American Association of Equine Practioners...
Most geldings are not interested in mounting and penetrating a mare. Yet there are some that will, especially one that is classified as a crypt orchid,(still has one testical inside the body cavity...