Five things to remember when worming
In our latest podcast, Victoria Murell (TBA) and Clare Daniels (TB-Ed) are joined by Prof. Jacqui Matthews, the Director of Veterinary Science at Austin Davis Biologics and an RCVS-recognised specialist in parasitology. They discuss how equine parasitic worms are getting smart, resisting some wormers and evading detection in some tests
- The importance of diagnostic testing
Rather than treating all adult horses with a wormer, it’s key to consider drug resistance and to aim to identify the animals that have a parasitic burden from those that don’t.
This targeted worming approach has three potential benefits: preventing anthelmintic resistance, minimising costs by treating only those horses that need it, and reducing the negative impact on the environment.
- Faecal sampling alone isn’t sufficient
Faecal sampling does not show an accurate picture of the full scale of the problem due to variances in worm life cycles and the different ways eggs are shed.
Faecal worm egg counts are a great tool for identifying the presence of large redworm in adult horses (typically, the 20% of the herd carrying 80% of the burden); and for measuring the efficacy of wormers (egg reduction testing and egg reappearance testing) post treatment.
- There are some differences between blood and saliva testing
These two types of ELISA test are similar, as they look for worm-specific antibodies. Results are presented in numeric values and exposure level categories, which your vet can help you interpret.
Blood testing does need to be done by a vet, whereas salivary samples can be collected by stud personnel or a vet.
The biggest distinction between these tests is that antibodies take longer to reduce in blood than saliva, therefore blood tests can be repeated after four months, whereas a horse’s saliva can be tested again after twelve weeks.
- Spring is the best time to test
The best time of year to test for Tapeworm is the spring. This is because a higher proportion of mature tapeworms will be present.
Body segments containing eggs become detached from the neck of the worm and then are shed intermittently in faeces. Mites act as intermediate hosts and eat the eggs, then horses will ingest the mites whilst grazing.
Autumn is also a great time to test for tapeworm, as well as small redworm.
- Effective paddock management is key
Optimising paddock hygiene is key to reducing parasite burdens. Regular manual or mechanical removal of droppings and cross-species grazing are recommended.
For even more details, listen to the full podcast here.
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