To Protect the horse’s intestines from trauma and inflammation by the de- wormer and the dying parasites; we recommend that you add 10 drops of colloidal silver, diluted in between 1/2 and 1 pint of non-chlorinated water, poured over the horse’s feed, 1/2 in the morning and 1/2 at night. Do the colloidal silver treatment for 4-6 weeks. Not all colloidal silver’s are created equal. We use a colloidal silver made in AZ.

If your horse is prone to or has stomach or hind gut ulcers, it is also recommended to use a pre or pro biotic with the de-worming. Start the protectant a couple of days before you start the de-worming. The best one we know of is KLPP from KAM. We carry this product at the clinic. We give the horse 15cc two times daily starting two days before the de- worming and continuing for two days after the de- worming. Our second choice would be a product called Pro-Bi, made by ABC. It is similar to KLPP, but less expensive due to the absence of saccharomyces boulardii yeast. It is dosed the same way as the KLPP. For horses with minimal gut problems, but still in need of some gut protection during de- worming; use Fast Track Equine Supplement. Feed as directed on the bag. All of these products are available in our office. You can look at them on our online store.

If your horse has not been de-wormed in over 4 months, or the de- worming history is unknown; you MUST give the horse a dose of ivermectin before you begin the protocol below. The ivermectin will do a SLOW, more gentle kill of any adult worms in the intestines, so that they don’t all die at once and pile up in the intestine. If all the worms die at once in the intestine, the horse can get an impaction colic. After you give the ivermectin, wait three weeks, and then proceed with the protocol below:

If your horse has been dewormed in the last 4 months, you can begin with the following protocol:

Give one box of Panacur dewormers, If your horse weighs between 900 and 1200 pounds, give 1 tube daily every day for 5 days in a row. (If your horse is less than 900 pounds, you need to adjust the dosage. If your horse is more than 1200 pounds, you need to add a double dose of panacur to each daily tube in the Power Pak). We usually add the additional wormer using single dose syringes.

After you finish the Power Pak, wait ten days from the last dose, then give a dose of Quest Plus using the correct dosage for your horse’s weight.

Do not underdose the Quest, or you will make all the worms sick, and then help them to develop reisistance to the de- wormer, without killing ANY of the worms. Do not overdose the Quest, or your horse could develop some temporary neurological problems.

Wait another ten days after the dose of Quest Plus, and then give your horse a dose of regular Quest for his weight.

This completes the recommended de-worming for L4 larvae.

If your horse is allergic to fenbendazole, the ingredient in Panacur, you can substitute the product Oxibendazole, found in Anthelcide EQ. Give a double dose of the Anthelcide EQ every day for five days in a row.


The American Association of Equine Practitioners is aware of the problem of the worms developing resistance to the de- wormers we currently have access to. One thing you can do to prevent further development of resistance to the de wormers we are currently using is to make sure to give your horse a dose that is adequate for his weight. If you dose your horse for less than his weight, you will make all the worms sick, and kill NONE of them. They will develop resistance to the de- wormer. Many states are successfully incorporating a system of only de-worming the horses that are shedders of parasite eggs. It seems that only a small portion of the horses seem to be carrying most of the parasites. We call these horses “shedders”. If we only de-worm the “shedders”, theoretically we will decrease the chance of resistance developing. The way this procedure is implemented is by testing the horses manure for the presence of parasite eggs about 2/3 of the way through the manufacturer’s recommendation for the duration of action of the de- wormer. The horses should have no or a low number of parasite eggs in the feces at this point. Those who have high egg counts are the ones we want to concentrate on keeping on a regular de- worming schedule. Those who do not have very many eggs can be de wormed less frequently or not at all. If your horse does show a high egg count after a certain type of de-wormer, you can try using a different ingredient (don’t just buy a different name brand of de- wormer, make sure you are using a different ingredient).

I have not had great success using the fecal test to determine which horses to de- worm and which ones to not de- worm here in Texas. Perhaps this method will work if the horses are not exposed to any pasture. Most of my clients have horses that graze on some type of pasture, and the ones who do not have parasites in their feces can still develop L4 larvae at their anterior mesenteric artery when they are not de- wormed for an extended period of time. We have also found that if we check the feces in the clinic we find many more parasite eggs than the lab does if we send the fecals out. It seems that the eggs are very fragile and seem to disintegrate before they reach the lab, but if the feces are checked while it is still very fresh, more eggs are visualized.

In this part of central Texas, if your horses are on any pasture at all, it is my recommendation to de-worm them every 2-3 months with alternating de- wormers.

Parasite load appears to be more linked with the horse’s strength of immunity than anything else. The best way to protect your horse from worms is to keep his immune system very strong. See other articles in the website for how to build a healthy immune system in your horse.

We have an example deworming schedule below:

  • Jan/Feb: Double Dose, (usually 2 tubes for a 1,000lb horse) of Pyrantel Pamoate (Strongid)
  • Mar/April: Oxibendazole or Fenbendazole (Anthelcide EQ or Panacur)
  • May/June: Ivermectin
  • July/Aug: Quest Plus (moxidectin and praziquantel)
  • Sept/Oct: Oxibendazole or Fenbendazole (Anthelcide EQ or Panacur)
  • Nov/Dec: Praziquantel Combination (Equimax or Quest Plus)

One of my clients found that the Valley Vet “Premium One-Year Wormer Pak” had all of the necessary dewormers in it if you buy one extra tube of Quest Plus, at a very reasonable cost.

The horses that we see in the clinic with EPM (Equine Protozoal Myelitis) these days are much less neurologic than the presentation many years back. I believe that a strong immune system will help protect your horse from EPM. Research says that 85% of the horses in Texas test as being exposed to EPM, yet only a small percentage exhibit any clinical signs. The horses appear to be developing resistance to the protozoa. We often find that EPM will come in after the horse has parasites at the anterior mesenteric artery, which weakens the immune system. We first treat the horse to kill the L4 larvae at the anterior mesenteric artery before we address the EPM. We will often give a product called Carbo Pellets and Epic liquid to improve the immune system of the horse that has the EPM. There is a all natural product called Sefacon that works very well as a protozoal killer. The Sefacon cannot be given within 5 days of any type of de- wormer. We carry these products here at the clinic. See our online store or call for prices. (512) 396 2234.