Odds & Ends

A cheat sheet on horse wormers

Posted on June 29, 2011 at 11:45 AM

This is my two cents on the different types of wormers.  While I am not a fan of unnecessary drugs or supplements, unless you are willing to have fecal analysis done consistently you need a wormer so that the worms are not sucking nutrients from your horse.   Worms are a fact of life for all animals, including people.  A limited amount will not hurt us.  However, since horses are now confined to pastures and eating grass where manure is close by, they pick up more worm eggs/larvae than they would in the wild.  Thus, we have worm medicines to limit their numbers.

I have listed the paste wormers that you insert orally every couple months.  Wormers are also available in a daily feed through variety.  I do not grain my horses daily, I prefer to increase protein through hay, thus a daily wormer is not practical in my situation.  I also use fly predators, and a feed through wormer will kill the predators when they come in contact with the manure.

Signs you need to worm?  Your horse rubs his tail/rump on stall, walls, posts; pot belly on an otherwise thin animal, not shedding out hair. 

Fenbendazole Wormers ~

Effective against:   Redworm, Pinworm, Roundworm, Stomach Hair Worm, Large-mouthed Stomach Worm.

Fenbendazole is a safe wormer; your horse can withstand an overdose of 100 times the standard dose.   For this reason, it is often used to clear out immature parasites, which are particularly resistant to wormers, by giving a dose twice a day for five days.

Safe-Guard is a popular Fenbendazole wormer.

Oxibendazole Wormers ~

Effective against:  Large Roundworms, Large Strongyles, Pinworms, Threadworms.

Oxibendazole may not target as many parasites as other wormers, but it is almost 100% effective on the ones listed.  Oxibendazole is a safe wormer and a horse can withstand an overdose up to 60 times the standard dose.

Anthelcide EQ is a popular Oxibendazole wormer.

Ivermectin Wormers ~

Effective against:  Redworms, Pinworms, Roundworms, Stomach Hair Worms, Large-mouthed Stomach Worms, Neck and Intestinal Threadworms, Bots.

Ivermectin is one of the most effective wormers available, although it is not effective against small encysted strongyle or tapeworms.  Ivermectin is a safe wormer and your horse can withstand a dose up to 60 times the standard dose.

Zimecterin and Equimectrin are popular Ivermectin wormers.  Generic Ivermectin is also widely available.

Praziquantel Wormers ~

Effective against Roundworms and Tapeworms.

Praziquantel is not effective against many types of parasites, but it is one of the few that will kill tapeworms.  It will target almost all parasites when paired with Ivermectin.

Praziquantel-Ivermectin blends are in Zimecterin Gold and Equimax.

Pyrantel Pamoate Wormers ~

Effective against:  Redworms, Pinworms, Roundworms, Intestinal Threadworms, Tapeworms.

Effective on tapeworms only at a double dose level.  Pyrantal wormers are safe for horses for horses up to 20 times the standard dose. 

Popular Pyrantel Pamoate based wormers are Strongid and Exodus.

Moxidectin Wormers ~

Effective against:  Encysted Small Strongyle Larvae and Bot Fly Larvae.

Moxidectin is controversial because while it is the only wormer that can kill the above parasites in a single dose, the overdose tolerance is only 5 times the standard dose.   Thus, overdose is easy on a foal or a weakened horse and it is only recommended for adult horses.

Quest is a popular Moxidectin based wormer.

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Reply Fjord Mom Corinne
11:58 AM on October 2, 2013 
LOVE IT!!! Thanks so much for putting together such a great cheat sheet. I've been needing something like this.
Reply Neal W. Welsh
5:35 PM on January 11, 2016 
Is Pyrantel Pamoate safe in dogs and effective in tapeworm infestation in canines? If so what is dose per pound of dog and what is the safety range? Thank you, Neal W. Welsh, ret. Vet. Tech.
Reply Cole-Ramos
2:16 PM on March 30, 2016 
In the South where horses gets bots year round, how can I rotate wormers when I see only ivermectn and moxidectin kill bots? I know Moxidectin as Quest and use it as part of my rotational plan but did not know the overdose tolerance is only 5 X the standard dose. I need something to kill bots every two months. Why would I use the others when they don't kill bots? Help!
Reply Hold Your Horses Stable
12:55 PM on March 31, 2016 
Bots have a yearly cycle. So worm when you see eggs. I found a university of florida article that said spring for fla. Worm for bots again in six months to kill the end of larvae cycle bots. Scrape eggs with a bot knife or sandpaper whenever you see them.
11:12 AM on May 6, 2016 
To ensure killing off 100 percent of p inwards how soon after giving Invernin do I give Pyrentec (sp? )
Reply lisa
10:08 AM on August 23, 2016 
Can you give us a calendar of wormers? What time of year is best to give each one of these products?

Thanks, Lisa

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