Unfortunately, there are plenty of horse owners still following an outdated program (from the 1960s!) of deworming by rotating products and treating their horses every two months or even more often. There’s more to worry about here than simply wasting money on excessive treatments. Here is an insight on why dewormer rotation is over and how parasites are becoming resistant to them.
Over time, overuse of dewormer allowed parasites to develop a tolerance for the drugs. Some parasites were killed, of course, but those that weren’t had better immunity to the deworming drugs, resulting in a parasite population that is becoming increasingly resistant.
We are now seeing widespread resistance to deworming drugs, particularly in the case of small strongyles, one of the most common equine parasites. Roundworms (ascarids), common in young horses, are also showing resistance. Because we only have three classes of deworming drugs available at this time, resistance is a serious issue, as it limits the available options to control parasite populations.
At present, fecal egg count reduction testing (FECRT) is the only method to detect resistance in strongyles, so it should figure into every horse’s deworming program. Your veterinarian can explain how and when to perform this simple test—and discuss the results with you so you know that you’re deworming properly.
Resistance among the following common parasites is cause for concern.
Read more about Regional Parasite Control for Horses >>
This article originally appeared in the April 2019 issue of Horse Illustrated magazine. Click here to subscribe!
Does time spent with your horse feel more distracted and scattered, rather than present and meaningful? If so, you’re not…
Welcome to Horse Illustrated’s weekly installment of the Right Horse Adoptable Horse of the Week, offered in partnership with the…
Strangles. The name of the disease itself can allude to a terrible demise, but most horses that contract strangles recover…
Colorado Horse Rescue (CHR) expands its lifesaving HorseAlert system to California to help horse owners evacuate safely during natural disasters.…
In last week's column, Dr. Diehl had just finished drawing blood to help determine the cause of Angus’s stubborn weight…
It's likely that at some point during a horse’s life, he will need to be sedated, either for a routine…