Buckskin

First of all, I cannot stress enough how important it is to keep records of when your horse was worned, and what with. Internal parasites can do some serious damage and even be causes of colic. If your horse is ill, and the vet asks "Is this horse wormed regularly?" Don't automatically say yes, say when and with what. REmember to read the package for the active ingredient.

This guide is to introduce you to some of the different types of drugs available for worming your horse. Many of you will be aware that worms can become resistant to drugs, so you should change what you use periodically. Whatm ost people don't realise is that it's the class of drug that needs to be changed, not the brandname.

Ivermectins: The Mectin group is commonly used and widely regarded as a 'wonder drug' because they affect so many types of parasites. However, this class of drug has no effect whatsoever against tapeworms. They are also limited when it comes to treating inhibited worm larvae. This group includes selamectin, ivermectin, moxidectin, avermectin and cydectin.

Organophosphates: These drugs aren't commonly used anymore because they can potentially be very toxic if overdosed, and there is a large degree of resistance to them in many species.

Piperazine: This compound is very safe to use, even on young animals, when treating for worms inside the gastrointensinal tract. It is also effective against cyathostomes.

Benzimidazoles: These drugs are commonly refered to as hte BZ's and usually end with a -dazole. They are effective against all adult strongyle-type nematodes (the main species), and are simple to administer as a paste. they aren't effective against inhibited larvae.

Praziquantel: This is effective against tapeworms, so is commonly sold in a combination with an Ivermectin.

Levamisole: This drug is not used in horses because it causes excitation.

There are more drugs underdevelopment, but these are the most common ones I've found.

Hope you find this useful.

ShortTail

If this is not used for horses, where should it be used?

This really a nice information regarding worming. How often do we need to give our horses these medicines in order for them to be free from worms? Or we should only give them the medicines if they have the worms already?

Buckskin

Levamisole is often used for other livestock such as cattle. There's a great belief out there that "If it worked for my cow it must also work for my dog, cat, horse and echidna". This is not always teh case, especially with cats and horses.

Each worming product will have a different duration of activity. Most will recomend worming every 6 to 8 weeks, as a preventative. Alternatively you can get your vet to run a diagnostic check for worms, as if you rotate pasture regularly and there's very little poo in the pasture there may be a low worm burden and less need to treat. It depends a lot on your local area's temperature, rainfall, soil type etc. As usual, the best person to ask specifically is your local vet.