All Natural Herbs to Improve Endurance in Horses Silver Lining Herbs introduces a line of products designed specifically to improve a horses over-all strength and endurance. Poor, low quality food can weaken your horse’s vitality. A healthy horse is a strong horse. Horses, by nature, are grazers and because of this their diet contains a variety of plants and herbs. Silver Lining Herbs has a special line of products that have been specially designed to increase your horses strength and endurance with 100% all natural supplements. Equine veterinarians and professional riders across the U.S. trust Silver Lining Herbs for their Champion horses and why shouldn’t they – its what their horses need!