| Amsinkia intermerdia - Common Name: Tarweed | | | | include at a minimum a CBC and a chemistry |
| & Fiddleneck | | | | panel. The blood panel can pick of signs of toxicity |
| A common weed in the desert southwest is | | | | prior to your horse being in full liver failure - giving |
| showing up in large volumes this year and causing | | | | you time for corrective action. Your doctor will |
| liver disease in horses & livestock. | | | | look for common signs of liver failure including |
| What is it? | | | | icterus (yellowing of mucus membranes & |
| A substance in the plant that is converted to a | | | | skin), unexplained hemorrhage, abnormal behavior, |
| toxin called pyrroles in the body. This toxin can | | | | weight loss and a poor appetite. Some horses |
| bind to DNA in liver cells and percent them from | | | | may also develop sensitivity to sunlight causing |
| undergoing cellular division and liver regeneration. | | | | dermatitis. |
| This process will continue as more & more | | | | The only definitive diagnosis is a liver biopsy but |
| of the weed is ingested until in a few weeks the | | | | many veterinarians will formulate a tentative |
| once healthy liver cells are replaced by scar tissue | | | | diagnosis based on history of the weed in the |
| (fibrosis) and the liver is unable to complete its | | | | horse's pasture and both laboratory and clinical |
| normal functions resulting in liver failure. Other | | | | signs. |
| tissues are affected in the horse in smaller | | | | What is the antidote? |
| amounts including the heart muscle and the lungs. | | | | Answer - none, the treatment consists of |
| Does it taste good? | | | | supportive care and early diagnosis of disease |
| Not really, typically horses on poor or limited | | | | with elimination of the weed form the feed or |
| pastures are the ones exposed to this toxin. As | | | | pasture. Commonly skin wounds are treated, fluid |
| the pasture is overgrazed only these hardy | | | | support is given and basically the horse is kept |
| weeds grow and the horses will then graze on | | | | alive giving time for the liver to make new cells |
| and ingest this plant. | | | | (regenerate) and heal. Thus the importance of |
| How Toxic is it? | | | | early action in removal of this plant for the |
| Very, as little as 15mg/kg in a horse over as few | | | | horse's graze cannot be overstated. |
| as 2 weeks can potentially cause liver failure. | | | | Please consult with your equine veterinarian for |
| Other estimates of toxic dose are between 1 | | | | assistance with your particular horse. Most |
| & 5 percent of body weight ingested daily | | | | veterinarians are more then happy to review |
| for 2 weeks. | | | | your feeding and pasture management system to |
| So how do I know if my horse has liver | | | | prevent a problem. Also regular interaction with |
| problems? | | | | you veterinarian will enable disease to be caught |
| Easy answer - Have you vet examine and run a | | | | and corrected early, potentially saving your horse. |
| blood panel on your horse. Blood work should | | | | |