A long-running court case serves as a reminder to be vigilant about the source and content of a horse’s grain. Twenty horses there were poisoned by a mistaken delivery of cattle grain laced with the antibiotic lasalodic in 1999. All the horses colicked and five died.
Source: EQUUS, July 25, 2021. Link.
Lasalodic and monensin are two common cattle-feed additives that are very toxic to horses. If they are accidentally added to horse feed or if even trace amounts are on the mill when horse feed is processed, the result can be very tragic.” – Ray Geor, BVSc, PhD