You can't give a horse anything to boost its endurance. The only way to boost a horse's endurance is to train it. You can boost its strength, or its speed, but not stamina or endurance. That is only acheived by training and good food.
It varies by the horse, but they do well in dressage, jumping of all types, eventing, and endurance.
Arabian
an Arab
Horse power
Long distance
Endurance riding
There are numerous ways to boost the energy of a horse. Here are a few....Give them a turnip, if you have any (gives a 10% boost)Feed them a carrot if their EC has any in stock (4% boost per carrot, yummy!)Feed them (but be sure not to feed them too much, or too little)Put them in the box or meadow (they eat in the meadow, and the box is not good for their morale, so it's an equal trade off)Give them a drink or a salt stone (2% boost from drink, more of a boost from the salt stone if they have a good amount of energy already).I've put up a link to my website, which has care tips that you might find helpful. =)
Simple lunging. Unlike humans, you can't build endurance by running into you give up. With horses, you should begin lunging for a certain amount of time that you are absolutely positive is comfortable for your horse. Then, as time progresses, lunge your horse a little faster or a little harder. Continue working up this endurance with gradual increases. If your horse should show any signs of exhaustion, immediately cut down on lunging time and speed. Give you horse about a week of this 'easy-lunge' period before starting to work back up to the former level. Make sure your horse receives the proper amount of food they need for the work they do. Always make sure your horse has plenty of water. Lastly, make sure you lunge them in both directions, as to balance the workout.
their is no one horse breed that is not good at dressage. look for a horse that has high comformation and endurance or ask the mods for their help.
Rocky Mountain Ponies
Yes
The turkoman breed of horse, which was noted for it's endurance, is sadly now extinct :( The akhal-teke horse is a modern descendant.