Hi everyone so just to throw an update out there. It looks like we have the situation under control for now, we dewormed all the cattle, gave them doses of oxytetracycline 4 days apart. Used a product vigantol AD3E (Made by Bayer) and another product which is called Hematofos B12 with iron. Unfortunately we lost a total of 6 cows. The cattle that were sticks and bones are still thin, but they are putting back weight and their calves look great. We still don't know the cause but we think it could of been the following.
Used the wrong dewormer either wrong amounts or some cheap stuff that never took care of the problem.
Cheap vitamins.
Not replacing needles after every cow,calf or sires get treated.
And the last one sounds a bit crazy, the cattle started to loose body condition at a higher rate with the minerals we were given them. I haven't spoken to the representative that sells the product, unfortunately down there they won't take responsibility if something happens. But so far things are better.
Thanks to all that pitched in with their thoughts and advise and how to nip this in the bud.