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Removing bot eggs

From: Karen

I just got some horses from out of state and they're nice healthy horses, with winter coats, but they have bot eggs on their legs. I didn't know this until a friend saw them and mentioned it...I had never seen them before. I have other horses here, and would not like to infect them with this, and was wondering if there's a way to remove the eggs, without shaving them off? It seems everyone has a different opinion on this, so I wanted to hear from you, since I trust your advice. I did already worm all 4 of them as well as all my other horses. But I really want to get rid of the little tiny yellow dots.

Thanks! Karen

Hi Karen!

You're right to want to get rid of those tiny yellow dots. Bot eggs are a lot more dangerous than they look. Bots (Gasterophilus) are nasty parasites that lay eggs (those tiny yellow dots) on the legs of horses during the late summer and early autumn. If an attentive owner notices and remove the eggs, no harm is done. If the eggs are allowed to remain on the horse's legs, they will hatch when the horse licks his legs, and the larvae, after ingestion, will attach themselves to the lining of the horse's stomach. They can do a great deal of damage during the winter, and then, in the early spring, they will pass out of the horse's system, pupate in the ground, and become - you guessed it - bot flies. Those flies will lay their eggs on the horse's legs - and the whole cycle begins again.

The way to interrupt the cycle is to remove the bot eggs before they can hatch. There are a good many ways of doing this. Since warmth and moisture causes the eggs to hatch (that's why they hatch when the horse licks its legs), you can get rid of bot eggs by hatching them out and killing them yourself. People who like this method usually use a bucket of warm water, a sponge, and a bottle of flyspray. The warm, wet sponge is passed over the eggs, causing them to hatch, and then the flyspray is applied. Other people - less squeamish, perhaps? will mist the horse's legs with warm water, then pull off the eggs with their fingernails.

In the event, it doesn't matter how you do it as long as you get those eggs off your horse's legs. You can use the above methods, or buy a special-purpose bot knife with a curved, serrated blade. You can shave the eggs off the hair with an inexpensive plastic safety razor. Or - I find this to be the easiest method - you can scrape the eggs off with a "bot block", a light, rough-surfaced, porous block. If you use this method, you'll need to "sharpen" the stone regularly by scraping it across a sharp edge.

After a hard frost, you can use a deworming product that kills bots.

When you inspect your horse for bot eggs, don't look only at the legs. Bot flies deposit eggs elsewhere on the horse, too. Check its shoulders, belly, flanks, and mane. Also check its chin, its throat, and the underside of its jaw - and its lips.

One more thing to remember: Bot eggs that have been scraped off can still cause problems for a horse that ingests them, so don't remove the eggs in the pasture or in front of your horse's feed tub!


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