Progress 02/17/04 to 02/16/05
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? Kochia weed (Kochia scorparia) is a common, drought tolerant annual weed of western North America, especially in the more arid regions of the central and south western states. Kochia weed is poisonous to cattle and sheep, causing a variety of clinical signs ranging from acute death, blindness, central nervous system depression, liver and kidney disease and photosensitization. Kochia has a variety of toxic and potentially toxic compounds present in the plant including nitrates, oxalates, sulfates, saponine, and alkaloids. These alkaloids and saponins in kochia weed have the potential to cause liver disease, and therefore severe economic losses to the livestock industry. 2. List the milestones (indicators of progress) from your Project Plan. Using experimental sheep and/or cattle, the research to be
conducted will investigate if an endophyte fungus growing in lochia weed is associated with the clinical signs of liver disease when consumed by livestock. Kochia weed seed and the green plant will be fed to livestock for a period of 40-60 days to assess and describe the toxicity of Kochia weed. If proven toxic, ways to isolate and identify the fungus and the specific toxin(s) responsible for causing liver diseae will be developed. 4a What was the single most significant accomplishment this past year? Kochia ssed from storage and seed collected fresh were fed to Holstein calves and to hamsters. Neither produced significant clinical or histologic disease. The seed is 28% protein and appears to be quickly fermented. Rumen pH in treated calves decreased pH within minutes after dosing, suggesting the ground seed is likely to cause rumen acidosis. Serum biochemistries and liver biopsies were normal suggesting this kochia seed is not hepatotoxic. 4d Progress report. This report serves to
document research conducted under Agreement #54- 5428-4-0108N between USDA-ARS-Poisonous Plant Research Laboratory and Colorado State University. Additional details of this research can be found in the report for the parent project 5428-32000-011-00D The Toxicity of Pyrrolizidine Alkaloid-Containing Plants and Other Hepatotoxic and Neurotoxic Plants. Kochia weed seed was not proven to be toxic. However, we did investigate had several reports of kochia toxicity in southern Idaho and southwest Colorado. As poisoning is sporadic this may take several years until environmental and animal conditions are right for another poisoning outbreak. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Kochia weed has been associated with several different poisoning syndromes in livestock. It is extremely drought, salt and nitrate tolerant it often grows in sites with little competition. Kochia commonly accumulates nitrates and often
causes nitrate poisoning when it is included in hay. It may also accumulate sulfates and it has rarely been associated with polioencephalomalacia. Still other animals develop liver disease and photosensitivity. Other than the nitrate poisoning, these "syndromes" of kochia poisoning have not been reproduced. As kochia is a common weed throughout North America, and some are advocaating using some Kochia spp. as drought tolerate forages, more work is needed to bettr define and characterize kochia toxicity.
Impacts
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Progress 10/01/03 to 09/30/04
Outputs
4. What were the most significant accomplishments this past year? Two weaned calves, approximately 4-6 months of age (200kg body weight) with fully functional rumens, were dosed orally with kochia weed seed. The seed was analyzed for protein concentrations and other possible endophytes or alkaloids. The protein concentration was estimated to be about 24%. As this could potential cause rumen acidosis, the calves were closely monitored for rumen motility and acidosis. Initially, the calves received 0.5kg twice daily via stomach tube and pump. The dose was increased by 0.5kg per day until the total daily dose of the plant is 5. 0kg. This dose was maintained for 10 days. Physical examinations were performed on the calf daily. Blood, serum and urine samples were collected daily, and analyzed for blood counts, serum biochemistry and electrolytes. At the high dose, the calves developed diarrhea and intermittent anorexia. Though both had intermittent anorexia, both
gained weight. The urinalysis and urine pH suggested they were able to maintain a normal acid:base status. The hematology and serum biochemistry studies were also unchanged. This suggests that this kochia weed seed was relatively non-toxic. Additional studies looking at kochia weed and kochia weed seed from sites that have reported poisoning are pending.
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