Worms Can Kill, Warns Equine Vet Practice

Kirsty MacGregor An equine vet practice in Derbyshire is emphasising the importance of responsible worming following the sudden death of a seemingly healthy horse from severe worm damage. Kirsty MacGregor, MRCVS, of Bakewell Equine Clinic in Derbyshire, was called out earlier this year to examine a six-year-old horse which had suddenly dropped down dead in the field. The horse had appeared normal on the day of turn out. He was outwardly healthy and had relatively good body condition. He had been seen walking across the field five minutes previously but within minutes he had fallen in mid-stride, indicating a very sudden death. A full post mortem confirmed that the cause of death was ‘verminous thromboembolism’ - a fatal blood clot caused by severe worm damage. Kirsty MacGregor explained: “The large intestine was loaded with encysted small strongyle larvae and there was evidence that other worms had migrated to the arteries and the liver causing inflammation and damage. The horse also had lesions in the small intestine, which, although common, are likely to be associated with parasite migration and chronic gastric ulceration in this case.” The horse was kept on a large DIY yard with around 40 other horses and ponies. With so many individual owners it had proved difficult to implement a regular worm control programme although the yard owner and her liveries had tried hard to manage the situation. Kirsty continued: “This unfortunate case serves to highlight the tragic consequences of being unable to coordinate an effective worming programme. Subsequently we have carried out emergency dosing, treating all the horses on the yard with a combination of moxidectin and praziquantel (Equest Pramox – Pfizer Animal Health) to treat encysted small redworm and tapeworm. At the yard owner’s request we have also put together a worm control programme for all the horses.” Bakewell Veterinary Practice has seen a number of cases involving encysted small redworm infestation this year, presenting symptoms such as violent colic and weight loss which in some cases have proved fatal, so they have put together ten tips to help horse owners make sure they keep their horses safe from worms:

• Use diagnostics on a regular basis to build a picture of your horse’s worm burden.
• Understand your enemies – familiarise yourself with the main types of worms affecting horses.
• Select the wormer most appropriate for the parasite you are targeting, by looking at the chemical ingredients of each wormer, rather than just choosing the wormer for its name alone.
• Use a weigh tape or scales to make sure you dose accurately according to weight.
• Treat horses as individuals as well as a part of the herd to make sure they are wormed according to their need as well as for their environment.
• Worm new horses before they mix with your existing animals.
• Don’t overstock paddocks and do rest them wherever possible to let the parasites die off.
• Grazing with sheep or cattle on the same pasture is an excellent way to cut the worm population as they will ‘hoover up’ horse worm larvae which then die.
• Keep stables hygienic and clean feed buckets well.
• Collect and dispose of dung from the field promptly, at least every week as this will significantly reduce the number of worm larvae getting on to the pasture.

For further information and advice on equine healthcare visit www.bakewellvets.co.uk

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