My horse has a pretty good length tail and is pretty thick until the bottom and it gets kind of scraggily. My trainer thinks that for next year he's going to need a fake tail, but they are super expensive. Do you have any suggestions on out to get his tail to grow more?
It also helps to if you trim the ends of the tail bc it's just like peoples hair, when you get it cut it provokes ur hair to grow more and grow faster. I used to have the same problem with my gelding, he had such a crappy short scraggily tail when I got him and I would just brush conditioner into it and leave it sometimes and I would trim it every couple of weeks, now his tail is super thick and I have to trim it or it drags the ground.
Yeah MTG is great stuff! Just make sure you're putting it on a test spot first before you do the whole tail. You don't want him to be allergic and lose his whole tail!!
Another method that I use is putting in conditioner and not brushing it. I like to leave my tails alone until shows where I will MTG and bag the tail a week before, and then the day of the show wash it really well and condition it with Cowboy Magic or something. Makes it really nice and soft to brush through! Then after that I go back to conditioning and that's it.
Mostly you need to protect the ends of the tail. Wash and condition it thoroughly, making sure you don't pull any hairs out. You may want to trim the ends off so that they aren't below his fetlocks. Then braid it and put it in a sock. That will protect the ends, and allow it to grow out thick. I've never found that stuff like Cowboy majic or MTG helps me. Just good basic care of the tail and nutrition does the trick (oh, and take it down and put it back up at least every 2 weeks - if you don't, the area by the tail bone will get tangled and break off)
About thickness, it should- you can also try some conditioner. 
