Abstract. Toxicity following ingestion of the vagrant, foliose lichen Xanthoparmelia chlorochroa was identified as the putative etiology in the death of an estimated 400-500 elk on the Red Rim-Daley Wildlife Habitat Management Area in Wyoming during the winter of 2004. A single, unsubstantiated report in 1939 attributed toxicity of X. chlorochroa in cattle and sheep to usnic acid, a common lichen secondary metabolite. To test the hypothesis that usnic acid is the proximate cause of death in animals poisoned by lichen, domestic sheep were dosed PO with (+)-usnic acid. Clinical signs in symptomatic ewes included lethargy, anorexia, and signs indicative of abdominal discomfort. Serum creatine kinase, aspartate aminotransferase, and lactate dehydrogenase activities were considerably elevated in symptomatic sheep. Similarly, only symptomatic ewes exhibited appreciable postmortem lesions consisting of severe degenerative appendicular skeletal myopathy. The median toxic dose (ED 50 ) of (+)-usnic acid in domestic sheep was estimated to be between 485 and 647 mg/kg/day for 7 days.

Abstract. It is widely accepted that ratios of dietary copper (Cu) to molybdenum (Mo) lower than 10:1 may produce molybdenosis in cattle, especially if sulfur concentrations are more than 3,000 ppm. Some authorities suggest that dietary Mo concentrations greater than 10 ppm are hazardous to cattle regardless of Cu concentration, but anecdotal reports suggest that this may not be the case. The original purpose of the experiment described in this report was to investigate whether supranutritional supplemental Cu could protect cattle against relatively high dietary Mo. Pregnant cows were grazed on 1 of 3 pastures: 1 with only background Mo, 1 with an average of 13 ppm Mo, and 1 that averaged 230 ppm Mo. Half the cows on the Mo pastures were supplemented with 17 ppm dietary Cu, the other half with the dietary supplement plus Cu boluses. Molybdenum effects were anticipated in the groups supplemented with 17 ppm Cu; however, despite increased tissue concentrations of Mo, only the 230 ppm Mo/17 ppm Cu group exhibited any effects. Moderate Cu supplementation permitted cows to graze a site heavily contaminated with Mo with no adverse effects on general health or reproduction.

Two dogs, a 13-year-old spayed female and a 7-year-old neutered male, were diagnosed with pentobarbital poisoning. Follow-up investigation determined that the source of pentobarbital was the carcass of a horse that had been euthanized more than 2 years previously and that was also apparently responsible for the death of a least 1, and possibly 2, other dogs. The fact that the horse carcass remained lethally toxic more than 2 years after it was euthanized reemphasizes the necessity of proper disposal of euthanized animals.

ABSTRACT:Greater Sage-grouse (Centrocercus urophasianus) are a species of concern due to shrinking populations associated with habitat fragmentation and loss. Baseline health parameters for this species are limited or lacking, especially with regard to tissue metal concentrations. To obtain a range of tissue metal concentrations, livers were collected from 71 Greater Sage-grouse from Wyoming and Montana. Mean6SE metal concentrations (mg/kg wet weight) in liver were determined for vanadium (V) (0.1260.01), chromium (Cr) (0.5060.02), manganese (Mn) (2.6860.11), iron (Fe) (1,0196103), nickel (Ni) (0.4060.04), cobalt (Co) (0.0860.02), copper (Cu) (6.4360.40), mercury (Hg) (0.3060.09), selenium (Se) (1.4560.64), zinc (Zn) (59.264.70), molybdenum (Mo) (0.93 6 0.07), cadmium (Cd) (1.44 6 0.14), barium (Ba) (0.20 6 0.03), and lead (Pb) (0.17 6 0.03). In addition to providing baseline data, metal concentrations were compared between sex, age (juvenile/adult), and West Nile virus (WNv) groups (positive/negative). Adult birds had higher concentrations of Ni and Cd compared to juveniles. In addition, Zn and Cu concentrations were significantly elevated in WNv-positive birds.

The lichen species Xanthoparmelia chlorochroa is toxic when consumed by domestic sheep, cattle, and Rocky Mountain elk. Clinical signs exhibited by poisoned animals include red urine, ataxia, and muscular weakness that rapidly progresses to recumbency. Elk are unable to recover once becoming recumbent; however, most affected cattle can recover if offered suitable feed shortly following the onset of signs. At present, the pathogenesis and specific toxin(s) are unknown. As part of an effort to elucidate the proximate toxin, a method using ultra-performance LC coupled to MS/MS with negative-ion electrospray ionization has been developed to compare salazinic, norstictic, and usnic acid concentrations in X. chlorochroa collected from locales associated with lichen poisonings. Compounds were extracted from lichen samples with acetone and sonication. The stationary phase was a Waters Acquity UPLCTM BEH C18 (50 2.1 mm; 1.7 m particle size) column. The mobile phase consisted of an acetonitrilewater gradient. The precision of the method was confirmed by an SD below 0.4 (n = 9) for triplicate samples. LOD values were 200, 100, and 50 ng/mL for salazinic, norstictic, and usnic acids, respectively.