Pigweed can be very toxic if eaten in large quantities. Horses are unlikely to eat this plant unless there is no other food available. This weed seems to grow everywhere--from pastures to vegetable gardens, roadsides to barnyards. It is still toxic if dried and baled into hay. Pigweed, and its relative lamb's quarters can cause kidney failure. Other symptoms of pigweed ingestion may include:
- respiratory distress
- lack of coordination
Resources: Indiana Plants Poisonous to Livestock and Pets
Cooperative Extension Service, Purdue University
If you suspect poisoning from any plant or substance call your veterinarian immediately.