Wormer confusion

• Redworms (large and small strongyles) – very common, cause ill-thrift and disease. These worms migrate through th ewall of the gut, the large strongyles entering the circulation and the small strongyles encyst in the gut wall.
• Tapeworms – less common, implicated in some forms of colic.
• Ascarids and threadworms – very important in foals.
• Lungworms – uncommon, except in donkeys.
• Pinworms  - lay eggs around rectum causing irritation.
• Bots – the adult worms in the stomach rarely cause disease but the lies cause annoyance as they lay their eggs on the skin.

DRUGS AVAILABLE

Basically there are only 4 worming drugs on the market that are used to treat ROUNDWORMS:

Fenbendazole   Panacureither as a one-off dose or in the 5 day guardform.

Ivermectin          Eqvalan, Eraquell, Furexel, Noromectin, Panomec, Vectin & Equimax
These all contain ivermectin at 1.87% and each syringe contains paste to dose a 600kg horse. THEY ARE ESSENTIALLY THE SAME PRODUCT.

Moxidectin       Equest

Pyrantel           Strongid P & Pyratape P.
ESSENTIALLY THE SAME PRODUCT.
They treat roundworms at the regular dose, and roundworms and tapeworms at  the double dose.

• Equimax treats roundworms and tapeworms as it contains invermectin and praziquantel, a specific tapeworm drug.
  

EFFICACY

Resistance to Panacur is becoming common. This is particularly the case in situations where horses have grazed the same pasture for years and received regular treatment with Panacur. 

There has been some resistance to ivermectin in cattle but this is not yet a significant problem in horses. To our knowledge all the various forms of ivermectin are all as effective as each other.

Moxidectin (Equest) has a similar mode of action as ivermectin but is the most effective against encysted small red worms, a siginifance cause of worm problems and diarrhoea in horses.

 WORMING ROUTINE

The current recommendation is that the basis of your worming programme is the use of ivermectin or moxidectin and in spring and autumn the horse receives treatment for tapeworm. The standard practice is to use an ivermectin product one year and Equest the next.

It is recommended that horses wormed with an ivermectin wormer are treated every 8-10 weeks.  Moxidectin (Equest) only needs to be repeated every 13 weeks and therefore is only required to be given 4 times a year.

Tapeworms did not used to be considered a significant problems in horses, and generally that is still true.  However, with the greater effectiveness of ivermectin and moxidectin, tapeworm numbers in the gut appear to be higher than previously reported and they have been implicated in some forms of colic.  It is recommended that horses are treated for tapeworms twice a year, in April and September.