Horse Parasite Information

So you have already prepared for a beautiful morning ride: horse tack – checked, your horse properly fed and rested, and there seemed to be no bruise or scratch on your horse’s skin. But while riding, your equine companion seemed to not be in the mood. She feels weak and sluggish. So you decided to ditch your morning routine. When you checked her back in her stable, you noticed that her stool does not have the same consistency as the usual. So does she seem to be sick? Yes. Does she need immediate treatment? Definitely yes.

There are about 150 species of internal parasites that can cause grave harm to your equine friend. Here are just two groups of those parasites which you need to protect your horse from.

Strongyles (Large and Small)

Large strongyles are generally composed of bloodworms, redworms, and palisade worms, while their smaller cousins are comprised of cyathostomes and small redworms, and are usually contracted through contaminated water and through the food that they graze. Their life cycle begins as eggs which may seem harmless, but when they have gotten into the intestines, they mature and begin to inflict serious problems to your horse’s system. Some invade other organs like the liver and the blood vessels. Some take about 6 months to mature, while others take about 8 to 11 months.

For the small strongyles, it may even take years before they emerge from their hibernation. Unlike their bigger cousins, they don’t invade other organs. Instead, they encyst within the walls of the colon. At this stage, they become resistant to many dewormers, and would require special measures.

These can be the culprits behind your horse’s anaemia, weight loss, weakness and muscle wasting, and colic. Bloodworms can inflict too much harm which may result to heavy blood loss.

To combat these, you have to make sure of the cleanliness of what your horse eats and drinks. As an added measure, consistent deworming is recommended. For other concerns, it is best to consult a local veterinarian.


While the first group proliferate and mature in the digestive system, these roundworms reside within your equine friend’s heart and lungs. They are usually composed of ascarids and large roundworms, and are also ingested when eating unclean food and drinking contaminated water. They begin as eggs, and they turn into larvae once inside the heart and lungs. The natural tendency is for them to be coughed up out of the mentioned organs, but then they go to the stomach instead. It is there where they turn into fully-grown, egg-laying adults. They take about 3 months to begin repeating the cycle.

These parasites can cause coughing and pneumonia, liver damage and infection, diarrhoea pot belly, rough hair coating, colic, and slow growth. If the problem has not been addressed as soon as possible, they can inflict more serious consequences such as intestinal blockage, even rupture.

Consistent deworming is a must. However, you should take note that foals and those that are 2 years old and below are more susceptible to this than the older ones.

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