Why Worm your animals.

Test, Identify, Treat.

for optimal control of parasitic worms. 

A suffolk ewe suffering from a heavy worm infection.


All large animals in the UK likely are exposed to a parasite of some kind at some point in their lifetime. Most parasites of concern often reside in the gastrointestinal tract and cause significant damage. Once matured into their adult forms, these parasites begin to lay eggs which in turn pass out of the host via the faeces.

Although gastrointestinal parasites are collectively of greatest importance, there are other parasites which live in other areas of the body.

Whats so bad about worms? 

These parasites can cause a range of clinical signs from a dull coat to death in extreme cases. Other common signs include loss of weight, lethargy, ill thrift, diarrhoea, bottle jaw, colic, jaundice, and anaemia. As a result, it is reported these ill effects and treatments cost the UK farmers £270M a year! (Journal Preventive Veterinary Medicine 2020).

a sample of sheep (ovine) faeces with tapewoem egg sacks (segments)
A test tube rack with 4 centrifuge tubes containing a slurry from faecal worm count samples

Despite industrys best efforts some parasites have become resistant to treatments we use. This means we must change how we approach controlling parasitic infections, so we can prevent anymore resistance building up. If not, we will return to an era where we struggle to have a horse fit enough to carry a rider, struggle to finish any livestock for meat, and our cows are too thin and ill to produce milk.

However! All is not lost yet! We can change how we control these worms to ensure we can keep our animals safe and healthy.


First TEST. Testing to understand the parasitic burden is of utmost importance, as this very often shows that there is not a parasite burden to treat against!

However, if there is an infection this IDENTIFYS what species of worms are present. This the next important point. As it is not commonly known, but all wormers DO NOT kill all species of worms! This is why, it is critical to know what you are fighting against specifically.

Finally TREAT. Once an infection is diagnosed and the right worming product is selected, it is vital that each animals gets the right dose! If not, the whole process is pointless. Treating, is almost always done by the weight of the animal. Therefore, accurate weights either measured or estimated, need to be accurate to ensure the right amount of drug is used to treat the infection. When using a dosing gun on a large group it is important to calibrate the equipment initially and throughout the group as this can easily change! TESTING again will monitor any resistance there maybe to the drug you used, which can be noted for next time you need to worm your animals.

TESTING should be done periodically throughout the year, especially in the springtime and autumn when most worms are at their most infective.

a group of healthy suffolk ewes grazing in the sunshine
a sample os MIC Animal Services faecal egg counting sample collection kits.

There are many other management choices all stockmen/women make throughout the year which can affect the rate of parasitic infection, these decisions range from buying in and quarantining new livestock, to grazing certain areas of the farm at specific times of year. 

The benefit from this method of parasite control is that you are only buying wormers when they are absolutely needed. You are not stressing the animals out by routine worming all year round. This results in a lot of money being saved from only worming the most heavily infected of the group, or by worming when the worm burden is starting to cause health issues or a lack of yield. By initially testing you then know how many worms you have, which means you can then re-test your group to ensure your wormers are still effective to the worms you have. 

A pair of red poll crossed with lincoln redred calves laying together