Another Can of Worms?

["Karen Steenhof" <steenhof@cyberhighway.net>]

Again, this may or may not be related directly to endurance.  But because
the health of our endurance horses is paramount, I was beginning to feel
guilty about NOT passing this along.

Has anyone else heard of problems with using the new wormer QUEST?

Last week I took my horses to the vet for their spring vaccinations,
Coggins, teeth floating, and sheath cleaning.  I told the vet I would worm
them myself and was thinking about using QUEST (which I had already bought).
He said DON't use QUEST!  He has done colic surgery on several horses that
had recently been wormed with QUEST (< 1 week) and feels that the colic was
related to QUEST's toxicity.  Although QUEST is ivermectin-based, but Fort
Dodge has modified the ivermectin molecule.  Unlike the old ivermectin,
QUEST interacts with fat differently.  I may have some of this wrong, but
apparently Quest is stored in fat.   Lean horses may get too much wormer in
their system. Unlike some other wormers, Quest needs to be fed according to
the weight of the horse.  The entire tube dose for 1350 pound is TOO much
for an 800 or 900 pound animal.  After talking to some people about this, I
have heard that some horses have developed  hives after getting QUEST.  I
have not read about any of these problems in the various horse magazines,
nor have I heard any thing about it on ridecamp.  But some of these problems
seem too serious to ignore. Does anyone have any experience or insights-- or
would anyone like to buy my 3 syringes of QUEST????

Karen Steenhof
Boise, Idaho
steenhof@cyberhighway.net