This chart was made by HorseSaddleShop for informative purposes only. You always want to consult your Veterinarian before treating your horse. In some cases, your Vet will come up with a rotational worming schedule directed especially for your born, as they will know the risks for parasites in your area.
Some prevention to parasites can be made by cleaning manure out of pasture frequently, as well as feeding your horses from a feeder rather than the ground.
Here are some factors that can result in a higher risk of parasites for your horse: