In Arabian show horse circles, it's a common practice to condition the horses' tails with a special hot oil. This treatment, along with other horse grooming practices, helps create those luxurious, flowing tails, but it can be difficult to do- to find the oil, find a way to heat it, etc.
A few years ago, browsing a beauty aisle at the store, I decided to try an alternative and was delighted to find it worked just as well with a faction of the hassle this type of tail conditioning usually takes: hot oil capsules! Vo5 makes a hot oil hair capsule as does suave, both are very affordable and work equally well.
Each treatment comes in a small tube or vials. You just just soak the tube in hot or warm water for 1 minute (If you don't have hot water in your barn, try bringing a thermos or insulated mug of microwaved water), wet the tail, break the tube of oil and massage it in. Allow to sit on the tail for a few minutes, then shampoo with regular soap and rinse.
Repeat this treatment every 4-6 weeks for best results. Not only does this conditioning treatment leave tails soft and silky, but it is an excellent pre-treatment for detangling a tangled, knotted, or matted tail. This same treatment can be used on trouble manes, as well.