It was time for me to deworm my guys and I misplaced my “schedule”, so I decided to go online and print one. Bad idea! There are so many deworming schedules out there…it is easy to get overwhelmed.
I found a deworming quiz that was incredibly helpful when deciding what schedule and dewormers are right for my horse. The quiz & the below information was written by Karen Hayes (an Idaho-based equine practitioner) and was published in the June 1999 issue of Horse & Rider magazine. –
See more at: http://www.equisearch.com/artic/eqdeworm321#sthash.7cTzzRGc.dpuf
QUIZ: Now see how you score on the following eight questions to determine which program is right for your horse.
1. Does your horse graze on pasture all year, increasing his chances of exposure to parasite larvae? (Yes=2. No=0.)
3. Does your horse nibble grass at other stables or public horse facilities-such as show grounds, fairgrounds, campgrounds, and/or highway rest stops-increasing his chances of ingesting parasite larvae? (Yes=5. No=0.)
4. Has your horse ever shown signs of heavy worm infestation? (Symptoms include a poor haircoat, weight loss, recurrent colic, or sloppy manure; or a fecal egg count of more than 100 eggs per gram.) (Yes=4. No=0.)
5. Is the collected manure at your horse’s facility spread on the pasture as fertilizer, increasing the chance of parasite larvae in his grazing pastures? (Yes=3. No=0.)
6. Is “dropped” manure in your horse’s grazing areas spread out with a harrow at least once a year? (Yes=3. No=0.)
7. Do you have a hard time keeping track of which dewormers can be used in a rotation program-possibly disrupting a purge program?(Yes=2. No=0.)
8. Do you delay scheduling your horse’s regular-care appointments, such as farriery, dentistry, vaccinations, and deworming? (Yes=3. No=0.)
Here’s what your total score means:
0-8: Your horse’s management and general condition are good enough that a well-timed purge program probably is adequate. It’ll minimize parasite eggs in his manure, and his risk of internal damage from worm larvae picked up in the environment is probably minimal. (Exception: If you answered “yes” to questions 3, 4, and/or 5, risk of damage increases; consider a daily dewormer.)
8-15: You’re in a gray area. Although a well-timed purge program will minimize worm eggs in your horse’s manure, other factors- such as a high concentration of parasite larvae in his environment- may expose him to internal damage.
Whether you choose purge or daily deworming, you won’t kill some dangerous parasites unless you take additional steps. These troublemakers are bots, tapeworms, and encysted cyathostomes (one of the most destructive immature forms of small strongyles).
Here’s a general program to fight these parasites, but check with your vet to develop a program right for your horse and your particular area.
Bots. Ivermectin and moxidectin are the only available products effective against bots. In a purge deworming program, you can kill two birds with one stone by using one of these products on your regular late-fall and spring treatment dates. Time of year is critical, because fall’s’ first frost kills bot flies, giving you a leg up on reducing their population-especially if you follow up in the spring. Here’s what to do: After first frost, remove/kill any remaining bot eggs or larvae on your horse’s legs with a bot block or knife. Then use a purge dewormer to get rid of adult bots in his system. In spring, remove/kill any external eggs or larvae you may’ve missed in the fall, and deworm him again to zap any adult bots in his stomach before they lay eggs. Then you’ll start bot season (spring through early fall) with a clean slate.
If your horse is on a daily program, give him a dose of ivermectin or moxidectin in early spring and again in late fall, in addition to the daily dewormer.
Tapeworms. Some investigators believe daily deworming effectively controls tapeworms, but the evidence is conflicting. As an extra measure, you have three options:
1) give pyrantel pamoate (Strongid P or T), at twice the usual dose, 2 days in a row;
2) give pyrantel tartrate (daily dewormer), at 10 times the usual daily dose, 2 days in a row; or
3) use of the canine tapeworm medication prazi-quantel (Droncit), which your vet can prescribe for oral use in your horse (about $45 a dose).
You can use options one or two to replace your horse’s regular deworming treatments in spring and fall. Give Droncit in addition to the regular deworming treatment, but on a different day, to avoid possible drug interactions.
Encysted cyathostomes. Prevent encysted cyathostomes by putting your horse on a daily deworming program, or kill them by:
1) using moxidectin as a spring and/or fall treatment in your purge deworming program; or
2) replacing a regular spring and/or fall purge treatment with fenbendazole at twice the usual dose, for five days in a row.
Daily verses Purge Programs
For daily programs, it’s critical that your horse gets his daily dose daily, as missed doses will decrease the levels of dewormer in his system, rendering it less effective- See more at: http://www.equisearch.com/article/eqdeworm321#sthash.7cTzzRGc.dp
For purge programs, timing is key. If you treat too early, targeted worms will be too immature to be affected by the dewormer. If you treat too late, adult worms will have the opportunity to produce eggs, infesting your horse’s environment and raising his (and other horses’) risk of exposure.
I hope the information was as helpful for you as it has been for me. For more information on worming and a comparison of the products available click the link below.
PHHWV Equi Info Note – Equine Worming.
The Chances We Take 
