Deworming Horses
When it comes to worming horses that are a couple things that I recommend. Firstly, consult your veterinarian as to the proper worming schedule for your horses. many horses that are simply kept in pasture don't need to be wormed very regularly, just twice per year or so. I would recommend having a fecal done on your animals to see the need for worming. To prevent resistance, you don't want to worm more than necessary.
You also want to make sure that you are rotating your wormers. If you are using the same type each time, you may not be killing all the bugs, meaning that there will be a little left over and those bugs will develop a tolerance. This is another way we can help prevent resistance.
There are 3 main types: Ivermectin, Strongid/Pyrantel and Fenbendazole/Panacur.
Watch your package labels, because many times the only difference in the cost of the wormers is the flavoring and additives.
Consult your vet as to which is better for you and make sure you are rotating the wormers!
Tube wormers work best since you can provide them the proper dosage per horse. There are however feed wormers that you can use that will mix with their grain.