Take the Parasite Pop Quiz! Learn Key Facts That Could Save Your Horse's Life.

Take the short Parasite Pop Quiz and test your parasite  IQ!  Knowing the answers to these 11 true or false questions could save your horse's life!

QUESTIONS:  TRUE OR FALSE

1. Large strongyles are the most dangerous parasite for horses.
2. There is a single wormer that kills all equine parasites. 
3. There are no negative ramifications if I underdose my horse on dewormer.
4. Horses naturally acquire immunity to ascarids (round worms) after 18 months of age.
5. The best way to manage pastures is to spread manure on them.
6. Hot dry weather kills parasite eggs better than freezing temperatures.
7. Small strongyles are becoming resistant to all available dewormers.
8. All horses on the same property will have the same worm burden.
9. A negative fecal exam means I never need to deworm my horse.
10. I’ve always used the same product. It works, so I don’t need to change it.
11. Moxidectin (Quest) should not be used on foals less than 6 months.
    
    

Answers:

1. Large Strongyles are the most dangerous parasite for horses. False
Almost all dewormers effectively kill large strongyles. Therefore they are quite rare and pose little threat to regularly dewormed horses.

2. There is a single wormer that kills all equine parasites.  False
Moxidectin plus praziquantel (Quest Plus) works well against encysted small strongyles, large strongyles and tapeworms.  However, it does not work well against ascarids in foals and should not be used on foals less than six months old. It is also important to switch classes of wormer to prevent resistant worms from developing on your property.

3. There are no negative ramifications if I underdose my horse on dewormer.  False
Underdosing horses leads to resistance by only killing the most susceptible parasites and leaving the strongest ones to reproduce.

4. Horses naturally acquire immunity to ascarids after 18 months of age. True
Young horses are very susceptible to ascarid impactions, and should be wormed regularly with fenbendazole (panacur) at a 10 mg/kg dose for 5 days in a row to kill them.

5. The best way to manage pastures is to spread manure on them. False
Spreading manure on your pastures can actually increase the parasite burden on your farm, unless the weather is hot and dry enough to effectively kill all the eggs.

6. Hot dry weather kills parasite eggs better than freezing temperatures. True
More parasite eggs are killed in hot dry weather then freezing temps.

7. Small strongyles are becoming resistant to all available dewormers. True
The adult version of small strongyles are fairly easy to kill while the encysted form are only susceptible to moxidectin for the time being

8. All horses on the same property will have the same parasite burden. False
Younger horses often have higher worm burdens because they have less immunity, and just like people, some horses have less immunity and some have more.

9. A negative fecal exam means I never need to deworm my horse. False
Fecal egg counts can quite often have false negative results, meaning that they come back negative but testing a different fecal ball or a different pile of manure from your horse would actually have a positive result.  Knowing that, all horses should be wormed a minimum of twice per year.

10. I’ve always used the same product.  It works, so I don’t need to change it. False
Using the same product over and over breeds resistance in your parasite  population. It also doesn’t kill all stages and types of parasite. Rotating wormers and using the appropriate one for the age of your horse is important.

11. Moxidectin (Quest) should not be used on foals less than 6 months. True
Horses less than 6 months of age have a higher incidence of adverse reactions, including ataxia, depression/lethargy and recumbency.  Very old and very thin or sick horses should also avoid moxidectin.

How did you do on the pop quiz?  What did you learn?  What worming products and protocol do you use on your horse?  Join the conversation and share your insights and ideas on the Stretch Your Horse Facebook page.

This Parasite Pop Quiz was developed by Dr. Flynn Magaorian, BVMS, a staff veterinarian at Oakhurst Equine Veterinary Services.  She is currently on maternity leave, but you can contact Dr. Jack Root or Dr. Sylvia Oullette (pronounced Wool-lette) at Oakhurst Equine if you have questions or need assistance devising an effective worming protocol for your horse.  (503) 554-0227.