Bot Fly

Lifecycle: Bot eggs enter the horse's mouth and develop into larvae. The larvae migrate and attach themselves to the mucus lining of the horse's stomach, remaining there during the winter. After about 10 months, they detach themselves and are passed in the feces. The larvae burrow into the ground and mature into adult flies. Adult females deposit eggs on the horse's legs, shoulders, chin, throat and the lips.

How It Gets Into Your Horse: The horse licks yellow eggs laid by G. intestinalis on its forelegs and shoulders. The eggs hatch and enter the horse's mouth. G. nasalis lays eggs around the horse's chin and throat. These eggs hatch and the larvae burrow under the skin to the mouth, wandering through the mouth before migrating to the stomach.

Dangers If Left Untreated: Bots can cause inflammation of the mouth and stomach irritation. Severe infestation can cause intestinal blockage, often leading to irritation, ulcers and colic.