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"Poisonous" does not mean deadly. Some manifestations of toxicity are subtle. The dose, as always, determines if a plant is safe source of nutrients or a toxic hazard.

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BRIEF: What can I do for my horse?

I have a mare that apparently has eaten something poisonous in the pasture or while I was at a rodeo a few weeks ago. She has photsynethis on her nose and lost appetire, partly because she has some sores in her mouth. I noticed the loss of appetite immediately and called the vet out. she has several very high liver enzyme readings, although she is still producing proteins and sugars. a CBC showed nothing abnormal but the panel was very high on AST it was 1088 and the normal is 205-555 . Also very high was the GGT HRS, it was 194 and normal is 12-45. Her TBIL was 6.8 and normal is .1-1.9. I am keeping her in the barn now during the day and she is going out in the evening and grazing for several hours. She is on grass hay only and sulfa pills with a shot of Vit B complex twice a week. We just discovered this on Monday, although I had noticed her being off her feed for three or four days prior to that. Is there anything else we can do for her..So far she is eating and drinking pretty good, but I am wondering if the worst is yet to come.


I don't know where you are, so I don't know your plants, but the secondary photosensitization and liver enzymes are consistent with a poisoning, perhaps by a pyrollizidine alkaloid bearing plant like grounsel (Senecio), fiddleneck (Amsinkia), or comfrey. At 22 years of age, there you could be seeing the cumulative effects of a lifetime of periodic low-key poisonings and disease on the liver, too. Ask your vet about the role of the sulfa in all this, too.