Actually, Larissa should get credit for my answer.
The kelp meal is about the cheapest thing you will find. Where you are located, it will cost about $50 for a 50# bag...which is enough to last about 400 days!!!
Melatonin works really good as well, but it is probably a little late to get much good out of it. I have done a LOT of Melatonin research. There are only 2 ways that I have come up with to really get the FULL benefit of Melatonin. You can buy the implants which will cost $75-$100 per month. It is a system that gets the Melatonin directly into their body through a slow absorption method in their ear.
The other way is to buy pure Melatonin powder, and chemically break it down with a solvent. There are a couple different solvents that work, but water and stomach acid are not two of them. Ethynol is the easiest thing to use. Ethynol, NOT Ethanol. Basically, you break it down with Everclear grain alcohol. It is really tricky to work with, and very unstable. You can mix it up, and put it in the freezer for a maximum of 1 week. After that, the alcohol basically kills the Melatonin. Once you have the Melatonin is a form that the body can absorb, you just mix it in with their feed or I suppose you can squirt it in their mouth. The mouth is the best body part to absorb Melatonin. That is the reason that Melatonin drops made for human consumption recommend that you place the drops under your tongue.
You can buy lots of liquid hair growth supplements designed for show cattle. The melatonin in these supplements is either in a dry state, or dry powder that is suspended in a thick liquid. It will still do some good, but not as much good as implants or a solvent solution. Melatonin pills will even work...the kind you buy at a drug store. They just don't work as well. These methods require the steers body to dissolve the melatonin, and it is not the most efficient method.
Last year we used one of the hair growth supplements. We gave it to 2 steers, and did not give it to 1. The steer that didn't get it actually had better hair. The reason he had better hair isn't because the supplement didn't work. It is because we worked harder on him. He was our best steer.
This year we are using the melatonin powder that I described above. In 3 weeks, we are seeing a significant difference. I would say more of a difference than we expected. The problem with making a claim that this is a wonder supplement is that this year has been unusually cool for us. We have not seen many days above 90 degrees, and that means very cool nights.
If you are the type that really likes boring stuff, read this.
https://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Sigma/Product_Information_Sheet/2/m5250pis.pdf