I don’t know of anybody around that when you start talking about lice, you don’t just innately get itchy. Lice are a big deal, and if they get out of hand then they can truly mess with your horse and make it miserable. The trick is to catch them before they get too crazy, the problem is that it’s the hardest time to find them. If you only have a few then they generally go undetectable.
A quick rundown of lice and what they are is appropriate I think, even though this information is everywhere on the internet.
There are two types of lice around and it’s easy to tell the difference. You’re either going to find brown ones or grey ones. The brown ones are chewers. They love to eat skin and nibble around all over the place. The grey ones are suckers, and not in the sense of “hey sucker, you lose!”, but of the type that are like vampires. They suck blood. If you have enough of them, supposedly there are cases where the horse has become anemic! That must have been a lot of lice.. supposedly it happens. Lice are a few millimeters long and horses have a lot of blood in their body, to be able to make one anemic is impressive for such a tiny bug. Anyways, most of the time they are chewers but either way they irritate the horse and cause them to scratch on all kinds of things to get them off. Either if they are getting their blood sucked or they are forced to scratch on all kinds of things, it’s an undesirable existence.
Lice like to lay eggs. They love it, one female can lay anywhere from 20 to 40 eggs. Amazingly the eggs aren’t much smaller than the nymph that just laid them too. Again.. lice are amazing little creatures. It’s undesirable to have them around, but scientifically and biologically, they’re pretty neat. These eggs will hatch in about 10 days or so. It will depend on if it’s warm and snuggly on the horse, or chilly and wet. Once they pop out of the eggs then they take another 30 to 45 days to become egg layers. Supposedly 9 out of 10 are egg layers too, so that’s something to think about if you’re good with math. To put it simply, one female can lay up to 36 female eggs on day 1, and by as soon as day 40 you could have another almost 1300 female eggs hanging around. It doesn’t take long to get to some incredible numbers. Hatch percentage is rarely 100%, but you get the idea. In about 5 generations you can get hundreds of thousands of the little fiends.
Lice love to travel, they always have their bags packed and will readily hitch a ride on another horse to spread around. This happens because horses love to snuggle and groom each other and in turn hopping a ride on another horse is easy. As lice like to hang out on the warm and fuzzy spots, you’ll find them at the base of the tail, all along the mane and forelock and sometimes on the upper part of the inner leg. Lice are great travelers too because they can hop off on a fence post, tree or blankets and brushes and are more than willing to wait for the next victim to wander along and then hitch a ride. Horses in confined spaces or just communal spaces should all be checked out if just one horse has been found to have lice.
If they aren’t infested then sometimes you have to look much closer. Watch for the signs of lice, like rubbing their faces and necks and tails/rumps on things. Obviously, like us, horses just get itchy. If they are itchy enough to remove hair, then likely they are having issues and you’ll need to step in to take a look. If there are only a few and they haven’t done much egg laying, then you’ll really have to search. A lice comb will help, magnifying scope and sharp eyes. Use bright lights. Lice tend to come out to the ends of the hairs when it’s too warm, so if you go on a good ride or even just bring in a hair dryer and get things warm in there, you may have a better chance at finding them.
Treatment is easy, prevention is easier. I once heard from a vet that you essentially want to put them in a shake and bake bag and throw them around for a bit like a good piece of chicken or pork, but obviously this isn’t possible. Bummer. This is in the case that you use basic delousing powder. It’s one of the more popular methods. In reality, it’s a manual job that takes time and being careful not to get anything in their eyes, mouth or nose. You want to get it all over their body and really rub it in. Wear gloves, eye protection and breathing protection. Not one of those lame mouth and nose protecting pieces of paper, get a good mask that has filters with high ratings. Delousing powder isn’t good for anybody.. especially the lice obviously. It’s poison, treat it as such and use common sense when applying.
Other treatments use creams, shampoos and internal drugs. Ivermectin is supposedly good, but essentially you are hoping that by poisoning the horse, the skin and blood will be poisonous too. Results will vary.
No matter what, you MUST follow up 2 weeks later with another treatment of anything topical you use. The reason for this is that you may kill all the lice in the first go around, but the eggs will still be there in whatever stage they are in. As it takes 40 days (about) to become egg layers, you can get the rest of them once they hatch (which as mentioned above, takes around 10 days). A 2 week waiting time to get those guys should be good enough. If you’re a nervous Nelly and want to be a careful Carl, then do it again in another 2 weeks to really get them all, but it’s doubtful it will be needed.
For those that worry about getting lice or passing them on to your friends, loved ones or hated ones, pets etc, don’t worry. Lice are picky and don’t tend to fraternize with those of other species. Horse lice snub their noses at the pig lice, cow lice, human lice, dog lice, cat lice and all the other ones. As do each of those lice, all assuming they are the higher species of lice and wouldn’t consider rubbing elbows with the lesser lice. It’s always smart to wash up and clean your clothes either way, but it’s very rare for lice to head on over to some other type of animal.
In conclusion, lice can be a real pest and they spread like crazy. Make sure to wash and treat all brushes and blankets that may have been used on a lice infested horse, clean your clothes too. Once you’re rid of them then that should be that, but keep in mind that you may get them again if a horse gets introduced to the herd that has them. Or you go to a show, or you share a brush, or you pet a horse that has lots of lice and then go to your horse etc etc. In other words, it’s easy to get lice and easy to get rid of them. Keep a sharp eye on your horse when grooming and take note of bald spots and rubbed areas. It takes but 2 minutes or so to give the areas a good look over to prevent the easily preventable.