A recent article by Sue Perry; "Did He Eat Something Poisonous?" in the Horseman's Yankee Pedlar outlined many of the common plants that pose a threat to horses.
Among those outlined were:
- Red Maple
- Cherry leaves
- Japanese Yew
- Cowbane (Water Hemlock or Cicuta virosa)
- Alsike Clover
- Acorns - Seldom a problem if other food is available, because horses seem to not like the taste.
The article was short and informative but in the limited space allotted they did not delve into more information.
One of the items not mentioned in the story is probably one of the most common grass types found in North America. Tall fescue (Festuca arundinacea) is the most important cool season grass in the United States. It provides the primary ground cover on some 35 million acres. Discovered In 1931 Dr E.N. Fergus of the University of Kentucky. It was introduced to the public as Kentucky 31, in the 1940's and 1950's it was extremely popular and was introduced to provide forage in areas where other grasses simply did not do well.
The problems with Fescue were later discovered and varied from foot ailments to weight loss, increase heart rate, increases in body temperature and lack of milk production in livestock who fed on Fescue; A fungus or (Fescue Endophyte) was found to be the culprit.
Since this discovery numerous studies have been done evaluating the threat potential of Fescue, it is widely understood that pregnant or nursing mares and young foals should not eat Fescue because of the potential for Fescue Toxicosis in Horses!
Another toxic plant not mentioned was White Snakeroot (Ageratina altissima) a highly toxic herb found mostly in Eastern North America.
While this information is important it is not a complete list of known hazards to horses.