This information is provided by Provet for educational purposes only.
You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.
Horse bots are the larvae of various "Gasterophilus" flies which worry horses and can cause serious stomach disease
The eggs of these flies are laid on the legs, or near the mouth of the horse and larvae hatch from the eggs when they are warmed by the horse licking them. Eventually these larvae migrate into the stomach of the horse where they cling to the lining causing damage. They can stay there for many months.
Regular grooming will help to remove eggs before they hatch, and the larvae themselves can be killed by using a wormer twice a year - examples of suitable wormers are haloxon and ivermectin.
Updated October 2013