What do I need to know about bots and my horse?


Well, bots are one of the many pests that can bother and potentially harm your horse.  Bots are a variety of fly, and even though they live part of the life inside your horse, they are not a worm.  Parasite, yes, worm no.  


The adult female botfly makes it her mission to lay about 500 eggs on your horse.  She will aim for legs, neck, and mouth area and will glue her eggs to your horse, mule, donkey, or zebra.  For some reason, she doesn’t like cows, which is good to know if you have them.  And by glue, I mean it.  Those eggs are not coming off voluntarily!


So how does her life cycle work?  The adult fly places the eggs on your horse.  Your horse rubs his legs with his nose, or maybe he rubs his buddy on his neck.  The eggs end up in his mouth, where they hatch into larvae and burrow in his cheeks and tongue.  They live there for a bit, then they migrate to his stomach and attach themselves there, also as larvae.  (This is fairly gross.  Ok, it's totally gross.)


Those little yellowish dots are bot eggs.  They are super sticky!

This is key - larvae do not lay eggs, so having a fecal egg count won’t tell you if your horse has bots in his stomach.  Once in the stomach, they like to attach themselves to the stomach lining and wait out the winter.  Come spring, they are passed with manure into the soil or manure pile and become pupae, eventually emerging as adult flies to mate and lay more eggs. 



A handy dandy bot knife will take care of removing eggs from your horse!


In many parts of the country, you have weather on your side.  Frost will kill any stages of bot that are not in your horse, so this is the time to join forces with your Veterinarian to administer anti-bot medication.  This assures your spring time manure pile won’t be full of bot pupae.  If you don’t have weather on your side, talk with your Veterinarian about a bot plan of attack.  



Grooming blocks (like the one above) and bot knives remove the eggs from your horse's legs, neck, etc so they won't end up in his mouth and continue the bot life cycle. 



You should also know that bots have been linked to weight loss, colic, indigestion, and other ailments of the GI system in horses.  Don’t take chances here!

How can you manage bots year round while you wait for the first frost?  First, manure management is key.  Bot pupae like to mature into adults in manure, so keep it picked up and composted and/or removed.  

Stay up to date on pasture management and rotation, also.  

Remove the eggs daily from your horses with a bot knife or bot comb, an inexpensive and handy tool.  

Practice good fly control.  You can read more about some fly control ideas here


How do you deal with bots around your horse?