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What causes sudden weight loss in horses? Worms, feed, or illness?

Updated on September 23rd, 2025

Pet's info: Farm Animal | Horse | Male | neutered

Drastic weight loss in horse just read about pin worms and adult strongyle are not easy to worm against as some workers are ineffective coupled with poor quality haylage which has been reported to yard owner could this be a reason to such drastic weight loss over such a short time?

1 Answer

Most Helpful Answer

Answered By Jennifer Summerfield, DVM CPDT-KA

Veterinarian, Certified Dog Trainer

Published on April 29th, 2017

Poor Jim! It's certainly possible for intestinal parasites to cause weight loss, and you're correct that they can be resistant to many dewormers - so it would be a good idea for Jim to have a fecal egg count done by your vet to determine if this is the problem. It's also possible that he may need to have his teeth floated, as this is another common reason for weight loss if he can't grind his food properly. Systemic illnesses like liver or kidney disease, cancer, etc. can also cause dramatic weight loss like this.

I would recommend having an equine vet come and out and examine him when you are able to - he/she can check his teeth and do a fecal exam, and may also recommend blood work or other testing if needed to help determine the problem.

1Pet Parents found this answer helpful

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