Most long horse lead ropes are made either of cotton or a soft flexible synthetic usually described as poly or nylon. The advantage of the cotton rope is that it is more likely to stay soft and not get stiff with age, while being stronger than the poly. It also tends to be less expensive than the nylon and is easier to cut in case of an emergency. The disadvantage of the cotton rope is that it will get slightly dirty or greasy from contact with oil and dirt. This can be overcome by hanging it up to dry in the garage or outside, on a drying rack in your bathtub or even on cardboard overnight until completely dry.
Horse Leads: Your Essential Tool for Equine Handling and Control
The other main advantage of this type of long horse lead rope is that it is spliceable. This is important because it allows the handler to attach it to a snap or halter with a simple sheet bend knot rather than using a metal clamp which can rust, bend or break. This is particularly important for horses who jerk back as it eliminates the danger of a metal clamp being caught in the mouth or throat.
The lead rope should be at least 10 feet (3 meters) long for training purposes. This is a good length for creating a safe distance between the horse and handler, while still being able to create a small amount of slack in case the horse tries to run off or gets agitated by something.