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Solitude IGR

SOLITUDE® IGR is a feed-through fly preventive that helps keep flies, and the diseases they can bring, away from your horses. SOLITUDE IGR passes through the manure of treated horses to prevent flies from developing into adults by inhibiting the development of the exoskeleton in fly larvae.

Add one scoop of SOLITUDE IGR into your horse’s daily ration to create a nearly fly-free environment in four to six weeks. Cyromazine, the active ingredient in SOLITUDE IGR, safely passes through the horse’s system and is excreted in the manure — stopping the life cycle of house and stable flies at the source.


  1. SOLITUDE IGR is fed daily to the horse and is excreted in the manure.
  2. House and stable flies lay their eggs in the manure, and the eggs hatch into the larval (maggot) stage.
  3. As the maturing larvae feed on the treated manure, they become unable to develop into adult flies because cyromazine, the active ingredient in SOLITUDE IGR, inhibits formation of chitin. Chitin is the base of the fly’s exoskeleton.
  4. The immature flies die.

Fly Life Cycle

Flies typically begin appearing and breeding once temperatures rise above 50°F. In more temperate climates, house and stable flies may breed year-round with peak populations occurring during humid months. Refer to the map to help determine the most effective time to use SOLITUDE IGR where you live.

SIGR map

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    • Studies have proven SOLITUDE IGR to be 100% effective against house flies and 99.5% effective against stable flies, with no effects on horses, other mammals or beneficial insects.1,2
    • 100% efficacy in inhibiting fly larvae development.2
    • Significant results may be observed within two weeks with full benefits realized between four to six weeks from initial administration.


    • SOLITUDE IGR has been safely used in horses since 2001 with extensive research to prove its effectiveness and safety in horses and the environment.3
    • It creates a healthier environment for horses, as threats from infectious disease vectors are minimized.
    • Greatly reduces the need for pesticide sprays and overhead fly systems, creating a healthier environment for horses, staff and riders.
    • Once excreted in manure, cyromazine, the active ingredient in SOLITUDE IGR, breaks down into a slow-release fertilizer and will not harm horses grazing in pastures with treated manure.1
  • To maximize the effectiveness of SOLITUDE IGR, horses must be fed individually. Made from alfalfa, SOLITUDE IGR pellets are top-dressed onto grain or mixed with the horse’s total ration to provide 300 mg of cyromazine (1 scoop) per horse per day.


    • One scoop (300 mg of cyromazine) of SOLITUDE IGR per day per horse, no matter the weight or size of horse
    • Available in two sizes:
      • 6 lb. pail (192 doses)
      • 20 lb. pail (640 doses)
  • Is it safe for nursing foals?
    A: We have seen no issues with nursing foals on SOLITUDE IGR.

    Q: Is cyromazine a prohibited substance for competition?
    A: SOLITUDE IGR does not contain any prohibited or controlled substances as defined on the current FEI Clean Sport List or USEF’s Forbidden Substances List. As official lists may change, Zoetis encourages you to visit www.feicleansport.org to search for prohibited substances. We also recommend checking the rule books for any other organization under which you compete.

    Q: How long will it take for SOLITUDE IGR to work on my fly problem?
    A: If you start feeding SOLITUDE IGR before your fly season arrives, you should see a drastic reduction in the fly population from the start. However, if you begin using SOLITUDE IGR after the fly season has started, you should notice a reduction in the fly population within four to six weeks. SOLITUDE IGR controls new flies from developing, so existing adult flies will remain. You may consider using an attractant fly bait to help speed up the process of getting rid of existing adult flies.

    Q: What do I do about the adult flies?
    A: You will always have a few flies around horses. To speed up the process of eliminating existing adult flies after starting SOLITUDE IGR, use an attractant fly bait. You can also use a topical spray to help control mosquitoes and gnats where they are a problem.

    Q: When should I start using SOLITUDE IGR?
    A: Ideally, you should start using SOLITUDE IGR about one month before your fly season normally begins. This could be anywhere from February to April, depending on where you live. If started early, you will see a drastic reduction in your fly population from the beginning of the fly season.

    Q: When should I stop using SOLITUDE IGR?
    A: Use of SOLITUDE IGR is recommended until cold weather inhibits fly development, typically below 50°F. This will vary in different parts of the country.

    Q: If I use SOLITUDE IGR, will all my flies be gone?
    A: You may always have a few flies around your facility due to migratory adults. These are adult flies that are passing through and have traveled in from other areas. To control migratory adults, consider using an attractant fly bait, which attracts and kills adult flies. You can also use a topical spray for other insect pests. As house and stable flies are opportunistic breeders and will breed in other material besides manure, you must also be vigilant with husbandry around the barn. That is why it is very important to make sure sanitation around the barn is maintained.

    Q: Is SOLITUDE IGR safe?
    A: SOLITUDE IGR is approved by the U.S. Environmental Protection Agency (EPA). SOLITUDE IGR is a nonorganophosphate that has a well documented safety and efficacy profile. It has been extensively evaluated in horses since 2001, as well as intensively studied in other species for more than 20 years.3

  • 1 Palma K. Study to Determine Efficacy and Safety of Pelleted Feed-Through Formulation Containing Cyromazine for Control of House Flies in Horse Manure. Triad Specialty Products. April 2003.

    2 Donahue W. Evaluation of cyromazine on the development of the stable fly, Stomoxys calcitrans, in manure from horses after an oral dosing regimen. June 2004.

    3 Palma K. Review of Cyromazine Safety Information. Triad Specialty Products. April 2003.