What you need to know about winter worming

Thursday 28th November, 2019

Horses are affected by worms throughout their lives, whether they are grazed all year round or not. At any one point in time, horses have a ‘worm burden’. When this burden reaches a certain threshold, a horse is considered to be infested and will require treatment to reduce the burden.

What is a worm burden?

A worm burden is the amount of eggs found in faecal matter, and relates to the number of worms within the intestinal tract. If the number of eggs reaches more than 300 per gram of matter, then the horse requires worming. If left untreated, horses can become very seriously ill, and in some cases, worm infestations can prove fatal.

What types of worms can my horse get?

There are many different types of worm that horses can host. Roundworm is the most common, second only to Tapeworm, Redworm and Bots. The UK typically has mild, wet winters, which means horses can ingest larvae late into the year. This makes winter worming essential to reduce the worm burden that accumulates within the gut wall while he grazes.

How can I check if my horse has worms?

Firstly, you would most likely see them in his faeces. Annual Faecal Worm Egg Counts (FWEC) on horse droppings will confirm the worm burden level and advise on appropriate wormer products. This test helps horse owners provide targeted worming for your horse. Fresh samples should be collected, therefore access to stabling is essential to ensure the results belong to their horse.

How do I treat worms?

Knowing when to treat your horse for worms is vital. It saves on costly blanket treatments that are not as efficient as targeted worming. Horses must be wormed at different points throughout the year, whether they are stabled or not, so here is the lowdown on what you need to know.

Roundworm is treated all year-round using wormers with different active ingredients at different times. An example of a common worming schedule is: Moxidectin every 13 weeks, Ivermectin every eight to 10 weeks, Pyrantel every four to eight weeks, Fenbendazole every six to eight weeks, or Mebendazole every six weeks.

Tapeworm treatment occurs every six months, around Autumn/early Winter and Spring/early Summer, so opt for a single Praziquantel-based wormer or double dose of Pyrantel-based wormer. Redworm is treated in November with a single dose of a moxidectin wormer of a five-day course of Fenbendazole.

Bots must be treated, with a dose of a Moxidectin or Ivermectin-based wormer, ideally after the first frost so that it kills off the adults. Repeat this process again in the spring prior to larvae maturing and emerging from your horse, so you have full protection.

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