Bots (Gasterophilus intestinalis)

Bots are the larvae of the bot fly

Small, sticky, yellow eggs are deposited on the horses coat by the female bot fly predominately in the late summer. The eggs hatch and the larvae get into the horses mouth when the horse licks its coat.

Bot eggs leg

Larvae in the mouth are then swallowed. Once in the gut the bot larvae attach themselves to the gut lining.They are eventually passed through the horses digestive system and are expelled in the droppings.

Bot eggs gut g larvae


Once expelled the larvae develop into the adult bot flies and the life cycle begins again. Bots can cause mild damage to the mouth and gums and also to the stomach lining.