Simply Horses Vets – The benefits of Worm Egg Counts

Simply horses Vets: The Importance of Worm Egg Counts in your worming program

We are rolling out some new worm egg count kits and just wanted to give you a bit more information about why it is important to use them.

We are now seeing widespread resistance to wormers that are frequently used, which means that the wormers are no longer killing the worms. This is occurring everywhere, not just in the North East. As well as this problem, there are no new worming drugs currently being created. This means we need to worm responsibly and try to prevent further resistance developing, so the wormers we are using will remain effective.

It has been found that approximately 80% of the horses in a herd, grazing on the same field, will be producing 20% of the worm eggs on that field. This means the remaining 20% of horses are producing 80% of the worm eggs on the field. It is important to target the 20% and reduce the amount of contamination they are producing. This is done using worm egg counts (WEC).

A faecal sample needs to be collected from all horses on the pasture on the same day. This will then be sent to the laboratory to identify worm eggs. If a horse has a low count of eggs, then they do not need to be treated (saving you money and helping reduce resistance). The horses with high worm egg counts need to be treated.

WECs should be performed 3-4 times a year. Some horses have a low count on one sample, but a high count on subsequent samples. This is because the samples look for eggs that are only produced by mature adult worms. If worms are present that are not mature then the WEC will be low, but once they are mature, they will start producing eggs that are detected in a faecal sample.

To help reduce worm burden in your horse and the amount of wormer that needs to be used, it is important to poo pick your pasture as well. This is especially important when doing WECs. As the eggs are passed in faeces and horses become infected by ingesting these eggs, the pasture needs to poo picked at least twice weekly, but ideally daily, to reduce the egg contamination on the grazing.

Even though you are doing WECs, it is important to worm twice yearly with a tapeworm product. Tapeworm eggs do not show up well on a WEC, so the best way to ensure your horse is protected is to have a blood sample taken or worm regularly for tapeworm.

What to do if you think the worms are resistant to the wormer you are using? In these cases a WEC needs to be done before treatment and then another sample taken 14 days later and compared to the original sample.

The vets at Simply Horses are carrying these new kits in their cars they are £9.50 each and this will reduce to £8.75 if there are 6 or more horses on one yard tested. They are easy to use and have everything you need to send your sample to the lab, the results are back in 24 hours direct to Simply horses where one of our vets will interpret the results and contact you with them and give you the best possible advice on what is the best course of action for your horse.