Damaged Hair
Hair damage can not be repaired, but it can be prevented. If the hair is as damaged as the picture above left, then the hair will have to be cut to prevent further damage. There are many factors that can damage hair; heat, sunlight & environmental damage (If you have seen black horses with an orange tint to the ends of the mane and tail then that is damage from the sunlight.) Using hair products with UV protectors are good, or keeping the mane / tail covered is also another way to prevent black hair turning orange.
Use of oil
When you put oil on her hair then it makes it shine, but it is only giving you the illusion of health. Oil molecules are too large to penetrate into the hair, hence it sitting on the outside of the shaft. Oil does not moisturise hair. We all know oil and water don't mix, so what you have done is create a seal (waterproof) on the hair. So now no moisture can get into it. The oil works great if you already have moisture rich healthy hair and you don't want any moisture to escape (hence a lot of African women using oil on their hair to prevent moisture loss), but in most horses (ones that I have seen) their manes and tails are dry so crying out for moisture and not wanting to be blocked from it.
Over time you will find that you have to use a strong shampoo probably containing DEA to remove the oil and then you will find the hair in its true state, very dry and dull. If you put oil on then you are starting the cycle all over again. The hair even though it has oil on will start to dry out and you may get some damage through breakage
another product that will cause the same problem are silicones. These fall into two groups - water soluble and non water soluble. Theses can form a buildup on the shaft and then you have created another seal to prevent moisture and nutrients from getting in. To name one non water soluble silicone 'Cyclomethicone' .. this is used a lot in detanglers. It does a wonderful job of removing knots, but long term use is not recommended, as it is not water soluble.
Some horse owners use 'Pig Oil' (Mineral oil) in the winter months on horses feathers to prevent mudfever, keeping the skin soft and the hair free from mud. Durring winter time the hair will not be dry so a little oil then is not as much as a problem as it is in the summer months. You would not want to use oil on the coat or skin in the summer months as it can result in the skin getting burnt. A lot of show horses will have oil applied to their eyes and noses in the summer for a horse show. I don't think an owner would want to stand out in the sun for 6 hours in a temp of 90 degrees with oil on their skin.
Ingredients in products
just some things that are good for your hair, or your horses hair :
If you can do a protein treatment at least 3 times a week. you wouldn't want to do it more than that as too much of a good thing is actually a bad thing. (so for human hair that if you wash every day use a moisture rich conditioner on the other days)
DEIONIZED WATER - Purified water that has had all minerals and chemicals removed.
hydrolyzed keratin protein - Protects hair shaft and helps retain moisture (this is actually one of the ingredients in Mega-Tek)
Hydrolyzed Wheat Protein and Wheat Oligosaccharides: this vegetable derived complex exhibits a unique and powerful moisture-balancing action that enables protein to control the moisture content of the hair.
Panthenol - It enhances the strength of hair and increases the resistance to breakage. It conditions without buildup and prevents damage caused by overheating and overdrying of hair and scalp. Panthenol nourishes hair by replenishing its level in the hair and imparts long lasting moisturization. Panthenol can also thicken hair by up to 10% (try and get a conditioner with this in)
CITRIC ACID - Fruit acid that adjusts Ph and tightens hair cuticle, adding brightness to hair color
Mucopolysaccharides - used to add body, moisture and shine to hair.
Things to avoid
Petrolatum/ Petroleum oil based
Mineral oil oil based
Lanolin oil based from the sebum of sheep
Cetearyl methicone not soluble in water
Cetyl Dimethicone not soluble in water
Cyclomethicone not soluble in water
Cyclopentasiloxane not soluble in water
DEA (diethanolamine)