deworming

Deworming Recommendations

Overuse of de-worming products is playing an important role in the development of parasite resistance. There are only a small number of drugs that will kill parasites available and no new products are being developed, so we must make what we have last!

It is important to only deworm your horse if he needs it, not by following the tradition of deworming on a set rotation every 2 months. In fact, some horses may only need to be treated twice a year. It all depends on how effectively your horse’s immune system functions to protect him from parasites in his environment. It is said that 20% of the horses in a group are responsible for 80% of the parasite load.

By counting the number of worm eggs your horse sheds in a gram of feces we can categorize him into one of three different categories: high, medium, or low shedder. We will then develop a de-worming program based on your horse’s immunity to worms and his environment. All horses will require fecal analysis twice yearly to determine parasite load. De-worming protocols for each of these categories is below. Treatments will be performed at specific times of the year to target the life cycle of the parasites.

October: BEGIN CYCLE

A Fecal Egg Count is performed on ALL horses at this time and repeated in January. For horses on this program, this count gives us a clear picture of how susceptible your horse is to parasites.

Each horse is classified according to the number of parasite eggs found in a gram of feces (eggs per gram or "epg"):

LOW (<200 epg)

MODERATE (200-500 epg)
HIGH (>500 epg)

LOW SHEDDERS

October 1^st : Perform fecal analysis. Administer Ivermectin.
January 1^st: Perform fecal analysis. Administer Moxidectin plus praziquantel

MODERATE SHEDDERS

October 1^st: Perform fecal analysis. Administer Moxidectin
January 1^st: Perform fecal analysis. Administer Moxidectin plus praziquantel

HIGH SHEDDERS

October 1^st: Perform fecal analysis Administer Moxidectin
January 1^st: Perform fecal analysis. Administer Moxidectin plus praziquantel
April 1^st: Administer Oxibendazole and/or pyrantel (if effective on your farm) or use both products together at the same time. … if it has never been performed, a Fecal Egg Count Reduction test should be done to determine efficacy of these drugs in your population. Another alternative is to administer fenbendazole at a double dose for five days (Panacur Power Pack).

No plan includes deworming horses through the summer months...why not?

All Horses: MAY –SEPTEMBER: No treatments are needed because it is too hot for transmission. Most worm eggs will not survive and develop into larvae, and those few that do make it to larvae will rapidly die. So egg shedding is of no concern during this time. Save money and reduce the selection for drug resistance by not treating horses with an anthelmintic (dewormer) during the summer months (unless there is a specific clinical need for such treatment).

From: Kaplan, RM. Suggested Worm Control for Adult Horses in Florida. Florida Equine Institute and Allied Trade Show. September 2009.

Common deworming drugs and their brand names:

Ivermectin:

"Equimax"

"IverCare"

"Zimectrin"

Moxidectin:

"Quest"

Moxidectin plus praziquantel:

"Quest Plus"

Fenbendazole:

"Panacur Power Pak" (5 days of fenbendazole at the double dose)