Out with the old, in with the new.
New deworming methods that is. In the past horse owners would deworm their horses every four to eight weeks to treat for intestinal parasites, but that is an outdated and incorrect method for treating intestinal parasites. By rotating dewormers every four to eight weeks, you are creating parasite resistance to dewormers, and if this method continues horse owners could be left without an effective parasite - control weapon. The goal of deworming is to limit parasite infections so animals remain healthy and illness does not develop. Worm larvae is killed by extreme weather so once the temperature gets above 90 degrees Fahrenheit it is too hot for the parasite to complete its lifecycle. Treatment in Florida should be done during fall, winter and spring
Before deworming your horse, a Modified McMaster Fecal Egg Count Test on your horses fecal should be done by your veterinarian to see if your horse is a low, medium, or high shedder of parasite eggs. The fecal egg count test is done to identify horses that persistently carry higher loads of parasite eggs due to their immunity. Ivermectin is an effective product for treating large and small strongyles in adult horses. After deworming 14 days later, you should also do a Fecal Egg Count Reduction Test to see if the deworming product used was at least 90 percent effective. If your horse is resistant to the ivermectin dewormer, a moxidenctin product can be used.
It is also important to deworm for tapeworms one or two times a year with a praziquantel product. Young horses are more susceptible to round worms and should be dewormed with a fenbendazole product every month for their first year.
Pasture management is also an important factor in controlling your horse’s parasite load. Maintaining the correct stocking rate on your property and not over stocking your pastures will help prevent overgrazing and will reduce fecal contamination. Clean and dispose of manure in pastures and mow pastures regularly to help break up manure and expose parasite eggs to the sun.
There is no such thing as a one size fit all program, so every horse owner should work with their veterinarian to develop a deworming program to fit their horse’s needs. If you have questions regarding a parasite control plan or pasture management plan contact your local Livestock Extension Agent.