Currently: Most horse owners do not know what wormers they are rotating or why. All horses are treated the same way on a farm. Farm owners are not aware of what parasites are on their farms or what resistance to dewormers exists on their own farms. WE CAN DO BETTER!
Reality: Adult horses vary in their genetic susceptibility to parasites, also referred to as their immune status. 20-30% of horses shed 80% of the eggs.
Why wait so long after worming to do first fecal? This is when egg excretion is optimal. This timing will reflect the immune status of the horse, rather than the efficacy of the last dewormer used.
Why do a fecal 2 weeks after first? This fecal will tell you if the wormer was effective, if given properly and at the correct dose. If not effective, then you have resistance to that drug on your farm.
Why twice yearly tests? This will tell you if your situation has changed due to the time of year, weather conditions, new arrivals, or any other changes.
Why deworm twice a year even in low shedders? In the spring, encysted larvae that have been hiding in the horse’s system may come vibrant again and start a problem. Encysted larvae do not produce eggs, so we would not find these on a fecal exam. In the fall the concern is bots, and tapeworms. Tapeworms can be difficult to find on a fecal exam. Bot eggs are laid on the skin, so we do not see them on a fecal.
If you have any other questions, give us a call at 410-535-9700.