Management Tips for Controlling Parasites in Horses

Equine parasite control and de-worming is a complex and sometimes controversial issue, but it’s a topic that’s been on my mind lately–thus the reason for this post.  I recently completed Dr. Kellon’s online short course on de-worming (which I highly recommend, by the way) and plan on implementing a new, revised de-worming program with my horses this year.

I won’t get into chemical or natural de-wormers in this post, but I would like to discuss some management practices that can help prevent and/or control internal parasites, aka worms, in horses.  Veterinarians estimate that as many as 50% of horse deaths can be attributed to internal parasites.  Eliminating all worms in your horse is impossible, but  the goal of any parasite-control program should be to reduce the chances of re-infestation to your horses.  Of course, many of these tips will require some work on the horse owner’s part, but it will ensure healthier horses in the long run.

Dr. John Kohnke, BVCs, RDA, says this in his article, New Strategies in Worm Control, “Over the last three decades, horse owners have been led to believe that complete control of worms of all types was possible with worming alone by the exclusive use of drugs at regular intervals. This has resulted in less emphasis being placed on pasture and other hygiene related measures to minimise re-infestation, allowing natural immunity to suppress worm activity and lack of strategic worming to help control seasonal worm burdens.”

I know that I have been guilty of this as well.  I’ve always kept a fairly clean barn, but I relied on the use of chemical de-wormers every three months to do the rest.  Of course we only do what we know, and in the words of Maya Angelou, “When you know better, you do better.”  With that in mind, here are some management tips for controlling parasites in horses:

Clean stalls and paddocks on a daily basis

This sounds fairly simple, but it’s something many horse owners neglect to do.  Especially the paddock areas.  Horses ingest worm larvae of by eating near manure.  If you feed hay on the ground, it’s especially important not to feed it on top of or near manure.

Compost manure for at least one year

There are several benefits of composting horse manure, one of which is killing parasites.  See this article for a guide to properly composting manure.  You can then safely spread the composted manure on your pasture without risk of re-infestation.  Or you can sell it and maybe earn back a tiny fraction of what you spend on your horses!

Rotate Pastures Regularly

If you have the space to do this, rotating horses among different pastures on a regular basis will help with parasite control.  A minimum three-month rest period is recommended for each pasture.

Chain-harrow pastures during very dry or cold weather

This will help expose larvae to the wind and sun, which will kill some larvae.  This practice is only effective in some areas, so it’s recommended that you contact a local agricultural extension office or university to see if this would be advised in the area where you live.

Don’t overcrowd pastures

Allow 1-2 acres per horse (more if you have poor soil).  This reduces the amount of manure your horses will be grazing around (obviously!)

Separate Horses by Age Group

This may sound like a strange tip, but younger and older horses are more likely to carry heavier worm burdens than mature, healthy horses.  Keep very young, middle-aged, and senior horses pastured separately, if possible.

Have fecal egg counts performed regularly

These tests aren’t fool-proof, but they are the best strategy for helping you to know which worms you’re dealing with.  You can then treat each horse accordingly.

Quarantine and treat all new horses before allowing them to inter-mingle with other horses

New horses may be bringing new parasites with them–parasites to which your horses haven’t previously been exposed.  Keep them separate, do a fecal egg count, and treat the horse accordingly before turning them out with the others.

Ta-ta!