Author
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Submitted to: Book Chapter
Publication Type: Book / Chapter Publication Acceptance Date: 10/1/2016 Publication Date: 3/1/2018 Citation: Stegelmeier, B.L. 2018. The pathology of select poisonous plant-induced diseases in cattle. In: Buergelt, C.D., Clark, E.G., Del Piero, F., editors. Bovine Pathology: Text and Color Atlas. Boston, MA: CABI. p. 381-417. Interpretive Summary: Under most conditions toxic plants only occasionally poison livestock; however, when toxic plants contaminate prepared feeds, alternative safe forages are not available, or some change such as grazing patterns, soil disruption, cultivation, or herbicide treatment increases plant availability, palatability or toxicity, poisoning can be devastating. Plant toxicity varies and there is extensive species and individual variation in response to plant toxins. Due to this variability, the diversity of disease presentations and the limited response animal response to injury, identifying plant intoxications is challenging. Though many plants produce suggestive or characteristic gross and histologic lesions, these are rarely plant specific. Diagnosis is usually dependent on field studies to identify which plants are available and have been eaten, clinical disease and clinical pathology, gross and histologic findings as well as chemical evaluation of tissues, serum, urine and gastrointestinal contents for plant toxins or their metabolites. Additionally many plant-induced diseases are similar or indistinguishable to diseases caused by other infectious, nutritional and genetic etiologies. The objectives of this work are to review the clinical, biochemical and pathologic changes characteristic of disease produced by toxic plants, introduce recent developments in our understanding and diagnosis of poisoning with common toxic plants, and outline current methods to identify poisoned cattle and better predict the outcome of poisoning. Technical Abstract: Under most conditions toxic plants only occasionally poison livestock; however, when toxic plants contaminate prepared feeds, alternative safe forages are not available, or some change such as grazing patterns, soil disruption, cultivation, or herbicide treatment increases plant availability, palatability or toxicity, poisoning can be devastating. Plant toxicity varies and there is extensive species and individual variation in response to plant toxins. Due to this variability, the diversity of disease presentations and the limited response animal response to injury, identifying plant intoxications is challenging. Though many plants produce suggestive or characteristic gross and histologic lesions, these are rarely plant specific. Diagnosis is usually dependent on field studies to identify which plants are available and have been eaten, clinical disease and clinical pathology, gross and histologic findings as well as chemical evaluation of tissues, serum, urine and gastrointestinal contents for plant toxins or their metabolites. Additionally many plant-induced diseases are similar or indistinguishable to diseases caused by other infectious, nutritional and genetic etiologies. The objectives of this work are to review the clinical, biochemical and pathologic changes characteristic of disease produced by toxic plants, introduce recent developments in our understanding and diagnosis of poisoning with common toxic plants, and outline current methods to identify poisoned cattle and better predict the outcome of poisoning. |
