Deworming

Worms can be very distructive to your horse. Here is a list of different worms and the damage they can do:

• Roundworms, or Ascarids, can cause colic, heart damage, liver and lung damage, and in older horses and foals can injure the gut.
  
  
• Large Strongyles, (bloodworms) can destroy arterial walls and blood vessels, impare circulation and lead to colic, anemia, diarrhea, fever, unthriftiness, brain damage and other disorders.
  
• Small strongyles can lead to inflammaton of the intestines, resulting in anorexia, weight loss and chronic low grade colic.
  
• Bots induce dental disease, stomach irritations, ulcerations and perforations of the stomach wall.
  
• Pinworms irritate the horse's tail region, causing tail rubbing.
  
• Tapeworms may result in severe ulcerations of the large intestine.
  
  

Horses need to be dewormed every 6-8 weeks in order to stay healthy. It is a good idea to switch dewormers every once in a while, to prevent the worms from becoming ammune to one wormer. Also, different wormers kill different kinds of worms, so if you rotate different dewormers, you will be sure to kill all different kinds of worms. Here is a table on different kinds of wormers and what they do:

Different Dewormers

Drug Class	Active Ingredient	Brand Examples	Form	Administration	Effective Against	Limitations
Benzimidazoles	Fenbendazole ______________ Oxfendazole ______________ Oxibendazole	Panacur ______________ Safe-Gaurd ______________ Benzelmin ______________ Anthelcide EQ	paste/granules/suspension ____________________ paste/granules/suspension ____________________ paste ____________________ paste/granules/suspension	every 6-8 weeks _______________ every 6-8weeks _______________ every 6-8 weeks _______________ every 6-8 weeks	En SS in h.d., L/S adult S, A, PW _________________ L/SS, PW, A _________________ En SS in h.d., L/S adult S, A, PW	Increasing resistance to benzimadoles by some parasites. Ineffective against bots. Allows reinfestation between deworming.
Macrocyclic lactone	Avermectin Ivermectin ______________ Milbemycin Moxidectin	Zimecterin ______________ Rotectin 1 ______________ Eqvalan ______________ Equimectrin ______________ Quest	paste ____________________ paste ____________________ paste/liquid ____________________ paste ____________________ gel	every 6-8 weeks _______________ every 6-8 weeks* _______________ every 6-8 weeks _______________ every 6-8 weeks _______________ every 12 weeks	Adult SS, LS, PW, A, THW, LW, HW, DH __________________ B, L/SS, En SS Lrv,PW, A, HW, SW.	Ineffective against TW and En Lrv stages of SS. Allows parasite infestation between dewormings. ____________________ Ineffective aginst TW. Allows reinfestation between dewormings.
PYRIMIDINE	pyranthel tartrate ______________ pytanthel pamoate	Strongid C ______________ Purina Colt & Horse Wormer ______________ Strongid P ______________ Rotectin 2	pellet ____________________ pellet ___________________ paste ____________________ paste	daily _____________ every 8 weeks _____________ every 6-8 weeks _______ every 6-8 weeks	L/SS, A, PW; D.P.C __________________ L/SS, A, PW _____________ L/SS, A, PW, Kills TW in h.d. _____________ L/SS, A, PW, kills TW in h.d.	Ineffective against bots. __________________ Ineffective against bots. allows reinfestation between dewormings. ____________________________ Ineffective against bots. Allows reinfestation between deworming. Doesn't kill migrating larvae. ________________ Same as above

*Supposed to be rotated with Rotectin 2
NOTE: Quest dewormer has been reported to have caused sickness and death in some horses

KEY:

D.P.C=Decreases Pasture Contamination h.d.= high doses En=encrysted TW=Tapeworms THW=Threadworms LW=Lungworms HW=Hairworms DH=Draschia Habronema

Lrv=Larva L/SS= Large & Small Strongyles LS=Large Strongyles S=Strongyles SS=Small Strongyles A=Ascarids PW=Pinworms B=Bots SW=Stomach Worms

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