The mild temperatures and abundant moisture recently experienced in New Jersey are primarily responsible for the abundance of flowering weedssprouting up in pastures and paddocks. While buttercups are usually not eaten and dandelions are not toxic at all, horse owners everywhere should be aware of a potentially dangerous “look-alike” called catsear.
Buttercups are toxic to horses; however most horses will only eat them if there is inadequate forage in the pasture and if they are truly hungry. If your horses have abundant, nutritious grasses also growing in their pastures and/or have free access to hay, do not panic if you see a few of these flowers as they likely won’t consume an excessive amount. If horses do eat a large amount,buttercups can cause oral irritation and pain.
Dandelions are not toxic and actually are fairly nutritious for horses, so if you see your charges helping with dandelion control, it is not cause for concern.
However catsear, which looks very similar to dandelions, is a potentially toxic plant for horses. It has yellow flowers that look like dandelion flowers, but the two plants differ in stem and leaf structure. Some ways to tell catsear apart from dandelion include:
Stems: Catsear has several stems with multiple flowers per plant, while dandelionsbear a single flower per plant.
Leaves: Catsear has soft, hairy, rounded/curved-lobed, and darker green leaves compared to dandelion with its hairless, lighter green, course/pointed, deeply serrated leaves.
Flower: Underneath the flower, the green leaf-like structures (sepals) cling to the yellow catsear flower. In dandelions, the sepals curl away from the flower.
Season: While dandelion blossoms in the early spring, catsear blossoms in the early summer.
Horses have been known to eat catsear even if other good forage is available, but a fairly large amount needs to be consumed before toxic effects occur. Catsear is suspected to cause stringhalt, a neurologic problem where the horse will suddenly flex its hind legs in an exaggerated and uncoordinated fashion. The condition caused by catsear is known as Australian stringhalt due to its prevalence in Australia and New Zealand. Stringhalt is also associated with vetch and sweet peapoisoning in horses.
Keep an eye on your pastures to ensure potentially toxic yellow plants don’t overtake your horses’ grazing area.