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Open Access Publications from the University of California

Scholarly Works (2 results)

  • Article
  • Peer Reviewed
UC Davis Previously Published Works (2019)
Backyard layer chickens may be exposed to a variety of metals in the environment, including lead. The potential public health concerns associated with lead exposure prompted us to systematically screen liver samples from backyard layers submitted to the diagnostic laboratory to estimate the prevalence of lead exposure. Over a period of 1 y, we tested 1,476 chicken livers, of which 45 were found to have lead concentrations of 0.9-41 µg/g. The lead-positive cases were investigated by follow-up questions to the bird owners on the environment, general management of the flock, and egg consumption of family members. Lead concentrations in 14 pooled egg samples were determined, and a conservative estimate of daily exposure of family members to lead was made based on egg consumption. In some cases, estimated daily lead intake exceeded the recommended limits for lead consumption in children. Analysis of feed, water, and environmental samples did not identify a source of exposure in most cases. Only 34% of owners of lead-positive birds submitted eggs or environmental samples, indicating a lack of interest or financial concerns. In most cases, neither the case history nor postmortem findings were indicative of lead intoxication; without systematically testing all birds, some cases could have been missed. Our study highlights the need for backyard chicken owners, veterinarians, and public health personnel to be aware of the risk of lead exposure and undertake preventive and surveillance measures.
    Cover page: Lead contamination in backyard chicken layer flocks in California.
    • Article
    • Peer Reviewed
    California Agriculture, Volume 76, Issue 4 (2022)

    Wildfires can drastically change rangeland by depositing ash contaminated with metals that are not part of normal diets. This can pose health threats to humans and animals. This risk, along with alterations of essential minerals in livestock grazing on regrowth on burnt lands, is not well known. To better understand this, our study investigated metal concentrations in water, soil, plant forage, and meat and wool of sheep grazing on the regrowth of burned lands. We compared metal concentrations in sheep grazed on regrowth to stored meat samples from grazing sheep a year prior to the wildfire. Lead, mercury, arsenic, molybdenum, cadmium, beryllium, cobalt and nickel were not detected above reporting limits in meat, wool or water samples. Contamination from chromium and thallium was detected in three of 26 meat samples from sheep grazed on regrowth. These metals were not detected in 22 stored meat samples from sheep the year before. Copper concentrations found in the meat of animals grazing regrowth was lower than in animals grazing unburned pastures; it is important to monitor copper concentrations in grazing animals to avoid diseases associated with copper deficiency.

      Cover page: Grazing lambs on pastures regrown after wildfires did not significantly alter metal content in meat and wool
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