Happy New Year!
Welcome to the January edition of the equine newsletter.
This month we are focusing on worming your horse for the year ahead.
Did you know that most horses have a worm burden? Whilst having worms in low number is normal, high levels can cause disease and (depending on the type of worm burden you have) clinical signs can include:
- An increased risk of certain types of colic.
- Diarrhoea.
- Weight loss.
- Poor performance.
Whilst a blanket worming approach used to be undertaken at regular times of the year, we now know that regular use of wormers can cause wormer resistance in the worm population. To ensure these products will work for as long as possible, we try to test droppings (faecal egg counting) to look at the number of eggs in the droppings to see what the worm burden is through the year. If there is a high burden, then treatment is appropriate at this point. If the burden is low, then retesting is appropriate 3-4 months later.
There are a couple of exceptions to using faecal egg counting:
There can be a lot of concern with encysted redworms. These are worms that bury in the horse’s large intestine in the colder weather like we have had. Because these worms are hidden away, detection in dropping is not possible. When the weather warms up, these worms hatch out which cause a lot of damage to the lining of the intestine and can result in life threatening colitis. This is where we have 2 options:
- Treatment with wormer such as moxidectin or a 5 day course of fenbendazole. This is best done after a short period of cold conditions (frost on the ground), so that we know we have targeted any encysted red worms present.
- There is now a blood test that can detect if the risk of encysted red worms is high or low. The benefit of this is that, if a high level is detected, treatment is warranted without over using the main wormer for encysted redworms which is moxidectin. This is one of the most effective wormers we have and protecting its use is crucial so that we have a wormer that is more likely to be effective in years to come. This option is appropriate if regular poo picking is part of management and your horse has consistently had under 200 eggs per gram of faeces through the year.
The other worm to consider is tapeworm. This is a worm where faecal egg counts are not always useful as there can be a period where tapeworms do not shed in the droppings, which may show a low level of burden even though a high burden may be present. A newer test has been introduced using a saliva sample which can detect a low or high burden.
Based on this, we recommend the follow plan (if you have an adult horse) to help maximise the chance your horse has a low worm burden without inappropriately using wormer all year round:
| December-January | Either: 1) If your horse has consistently had a low faecal egg count (under 200 eggs per gram) and the field if regularly poo picked, consider blood testing for encysted red worms. If a low level detected then start faecal egg testing in the spring. If a moderate or high level detect then treat with moxidectin or a 5 day course of fenbendazole. 2) Empirical treatment with moxidectin or a 5 day course of fenbendazole. Saliva testing for tapeworm. If low levels then re-test in 6 months. If high levels then treat with a pyrantel based product and re-test in 4 months. |
| March-April | Worm egg count. If the amount is greater than 250 eggs per gram of faeces, treat with a fenbendazole or ivermectin based product. Re-test faeces as advised to ensure there has been a reduction in the burden. |
| June-July | Worm egg count. If the amount is greater than 250 eggs per gram of faeces, treat with a fenbendazole or ivermectin based product. Re-test faeces as advised to ensure there has been a reduction in the burden. Saliva testing for tapeworm. If low levels then re-test in 6 months. If high levels then treat with a pyrantel based product and re-test in 4 months |
| September-October | Worm egg count. If the amount is greater than 250 eggs per gram of faeces, treat with a fenbendazole or ivermectin based product. Re-test faeces as advised weeks to ensure there has been a reduction in the burden. |
Some worming management regimes are different, which include youngsters and adults moving yards. If this is the case then please give us a call to discuss a worm management plan to help keep your horse’s worm burden at bay.
We offer faecal egg counts at the Southwell practice. The best sample is the freshest possible. Give us a ring if you would like one running. Ideally a day’s notice would be required to make sure we can prepare for the sample. Equally, let us know if you are interested in blood testing for encysted redworms or tapeworm saliva testing.
All the best,
The team at Minster Vets
