Question: I’ve heard about fecal egg testing prior to deworming, but when I looked into it, I learned these tests don’t detect bots and tapeworms. This means that I’ll still have to do treatments for those, even if my horse doesn’t need deworming for small strongyles. So why bother with egg count tests at all?
Martin Nielsen, DVM, PhD, DVSc, DACVM, DEVPC, of the University of Kentucky’s Gluck Equine Research Center, responds: Thank you for your question. You may believe that you can save a few bucks by skipping fecal egg count testing but, in fact, you may be wasting your money on ineffective dewormers instead. The issue is that without testing you will not know if the deworming agent you are using actually works.
Fecal egg count testing can tell you which horses in your herd need to be dewormed. (Getty Images)
We now have drug resistance in equine strongyles, ascarids, pinworms and tapeworms. We are finding more and more drug resistance every year, and we are not expecting any new products to become available in the foreseeable future. No single deworming product can be expected to work against all parasites of interest. If we just deworm without any kind of monitoring, we are making the resistance problem worse, and we may well give ourselves a false sense of security.
All parasites are not the same
A horse can harbor many different parasite species, but not all of them require treatment. Bots, for example, are low on the list of treatment priorities because these insect larvae are not associated with primary equine health issues. Therefore, we recommend against specifically treating for bots. When we administer an ivermectin treatment for other purposes during a time of bot infestation, we may get a reduction as a side effect. But we advise against letting bots dictate our deworming strategy. They are not important enough. We must keep our priorities straight.
Tapeworms: A growing concern
In contrast, tapeworms are a growing concern. Recent findings of tapeworms failing to respond to current dewormers are very concerning and will necessitate much more tapeworm testing in the future. We will no longer be able to just expect a tapeworm dewormer to be effective. In general, it has been believed that more advanced fecal egg counting techniques are required to reliably detect and count tapeworm eggs in fecal samples. Recently, however, we determined that some simple fecal egg counting techniques can detect multi-resistant tapeworm infections, indicating that these tests can provide useful information about tapeworm infection.
A test for resistance
The most important reason for determining parasite fecal egg counts today is to test for resistance. This is a problem that we all must help address: horse owners and veterinarians alike. Your veterinarian is your horse’s advocate. Yes, they also need to make a living, but their business is the health and well-being of your horse.
Think about it this way. You owe it to your horse to make sure the medications you are administering are 1) necessary, and 2) effective. If you don’t do any testing, you are doing your horse a major disservice.
Our expert
Martin K. Nielsen, DVM, PhD, DVSc, DACVM, DEVPC, is a professor of equine parasitology at the Maxwell H. Gluck Equine Research Center, University of Kentucky. His research is dedicated to providing solutions for equine parasite control. Nielsen’s work includes development and refinement of diagnostic techniques, objective evaluation of deworming regimens and anthelmintic resistance.
