The emergence of weeds in summer can present challenges for horse owners and hay producers. Reports by several New Jersey farmers indicate an increase in the prevalence of these weeds in the latter part of this year’s growing season, most likely attributable to recent weather patterns. A number of these plants are known to be toxic or otherwise harmful if consumed by horses.
Some weeds that do not produce a chemical toxin can still negatively impact horse health. Barbs from the seed heads of foxtail, for example, cause ulceration of the mouth, lips and gums. For additional information on foxtail, see this article from the University of Tennessee Extension: https://extension.tennessee.edu/WebPacket/Pages/WP-2015-12-Horsesandfoxtail.aspx.
It is important for horse owners and those harvesting forage intended for use as horse feed to monitor the species composition of their pastures and fields in order to prevent inadvertent consumption of harmful weeds by horses. Regular visual inspection of hay is also encouraged, especially any 2018 second-crop hay, and contaminated hay should never be offered to horses.
To learn more about which plants are potentially toxic to horses, please refer to this Rutgers Cooperative Extension Fact Sheet:
Additional information on poisonous plants for horses and other livestock species is available through the College of Agriculture and Life Sciences at Cornell University: https://poisonousplants.ansci.cornell.edu/php/plants.php
An upcoming webinar, on September 12, 2018 from 12-1pm, presented by Penn State Extension will also focus on toxic plants in horse pastures. Registration for this webinar can be completed on the PSU Extension website. https://extension.psu.edu/toxic-plants-in-horse-pastures