Imagine this:

You are squatting down beside your horse to examine its legs, something which is of the utmost importance with horses. The horse is tied up and its back is to the road that runs along side the stables. It is a quiet road, long and straight and easy to go fast on. Your horse is half asleep as you examine its legs. Suddenly, out of no where, comes a motorbike, loud and fast and just a flash of color in the horse's eye.

Your horse freaks and tries to run backwards, but because it is tied up it feels pressure and so gets even more frightened. It pulls with all its might on the cotton rope and brakes something tying it up and skids backwards, right onto you. While you try to get out of the way of the horses flailing legs its eyes are rolling and it has started to tremble and look around with fear. You try to calm it but it is still frightened. Meanwhile, your leg is bruised from where a sharp hoof hit it, perhaps it is even bleeding.

It takes several minutes to calm your horse down.

This is why motorbikes and horses don't mix.

Essentially, they are the same. They are single-rider vehicles, though you can go double, they go fast and if you attach a carriage to it more people can "ride" it. You can use them on farms, they are fun yet dangerous to ride.

But they do not mix. Motorbikes scare horses. And when a horse is scared, they are dangerous. They have sharp hooves and teeth and are really, really heavy, and even without momentum can crush you. People die around scared horses.

If you have a bike, do not ride it near horses. Go slow, very slow, around horses. There's miles and miles of road where there are no horses. Go fast there. You could be saving a life.