Equine Mycotoxins.

The main mycotoxins involved in adverse equine health issues are aflatoxins, fumonisins, trichothecenes, and probably ergovaline (fescue grass endophyte toxicosis). Most exposures are through contaminated grains and grain byproducts, although grasses and hays can contain mycotoxins. Clinical signs are often nonspecific and include feed refusal, colic, diarrhea, and liver damage but can be dramatic with neurologic signs associated with equine leukoencephalomalacia and tremorgens. Specific antidotes for mycotoxicosis are rare, and treatment involves stopping the use of contaminated feed, switching to a "clean" feed source, and providing supportive care.

Extensive Evaluation via Blinded Testing of an UHPLC-MS/MS Method for Quantitation of Ten Ergot Alkaloids in Rye and Wheat Grains.

BACKGROUND: Ergot alkaloids are mycotoxins produced by the fungus Claviceps, which can contaminate grains and pose a health risk to humans and animals. Validation of an ergot alkaloid method in collaborative projects can be challenging due to instability of analytes, a lack of reliable reference materials, and a fully validated reference method. OBJECTIVE: To extensively evaluate performance of a quantitative UHPLC-MS/MS method to detect ten ergot alkaloids at concentrations between 16 and 500 ng/g in grains. METHOD: The method performance was evaluated in the Blinded Method Test (BMT) exercise, which allowed organizers to successfully address the challenges. Forty completely blinded test samples were prepared in an independent laboratory and shipped to a participating laboratory to analyze on two separate days. RESULTS: Precision, accuracy, and HorRatr values met or exceeded the U.S. Food and Drug Administration recommendations. The design of the BMT exercise provided a high degree of confidence in data and conclusions drawn. CONCLUSIONS: The method performed in a manner as expected, and the method can be used by the laboratory for routine testing of wheat and rye grains. HIGHLIGHTS: BMT of laboratory methods facilitate validation of tests by evaluating performance in an unbiased manner.

Ruminant Mycotoxicosis: An Update.

This review focuses on factors associated with mold production in feedstuffs and major mycotoxins affecting ruminants in North America. Ruminants are often considered less sensitive to mycotoxins owing to rumen microflora metabolism to less toxic compounds. However, ruminants occupy wide agricultural niches that expose animals to diverse toxins under widely different environmental and nutritional conditions. Often the moldy and potentially highly contaminated feeds end up at feedlots. Less than optimal feedstuffs creating suboptimal rumen microbial flora could result in decreased ruminal capacity to detoxify certain mycotoxins and adverse effects. Numerous mycotoxins and clinical effects in ruminants are discussed.

Multiple episodes of 1080 (sodium monofluoroacetate) intoxication in a California calf-raising operation.

Over a 1-y period, a California calf-raising operation experienced 4 separate episodes of sudden death in 4-6-mo-old steers. Each episode occurred in 1-3 contiguous pens on 1 of 3 properties owned by the operation, but eventually all 3 properties were involved. In each episode, animals appeared normal at the evening feeding but at the subsequent morning feeding were found dead or dying. Remaining live calves had a stiff gait and were often dribbling urine, but did not show respiratory signs until they were down and agonal. At postmortem examination, calves consistently had moderate-to-large numbers of ecchymotic and suffusive hemorrhages on the epicardial surface and moderate-to-large amounts of fluid in the pericardial sac. Pulmonary edema and/or moderate amounts of watery fluid in the thoracic and abdominal cavities were present in a smaller percentage. On histologic examination, the myocardium had variable myofiber degeneration characterized by hypereosinophilia and fragmentation with mild interstitial infiltrates. Testing of heart and liver samples for monensin found levels lower than in previous cases of monensin toxicity. Rumen content was negative for oleandrin and grayanotoxins. Sodium monofluoroacetate (trade name: 1080) was consistently detected at ⩾10 ppb in kidney and liver, and was concluded to be the cause of the intoxication.

Ruminant mycotoxicosis.

Ruminants have the capacity to utilize some mycotoxin contaminated feedstuffs without impact on production or carry-over tissue residues. Despite large investments in crop development to diminish mold invasion and mycotoxin production, grain facilities to dry and store cereals, and use of alternative processing, mycotoxins frequently occur at elevated concentrations that affect ruminants. Fungal invasion by molds can occur in stored forages, silages, and wet bales and toxicity of these mold related mycotoxins is often poorly characterized. Ruminants occupy wide agricultural niches that expose animals to diverse toxins in different conditions, challenging veterinarians making diagnostic interpretations on contaminated forages and grains. This article discusses mycotoxins affecting ruminants in North America.

Ethylene glycol toxicosis in adult beef cattle fed contaminated feeds.

Acute deaths of cows held in a drylot and fed several crop processing plant by-products were investigated. Clinical signs in affected cows included diarrhea, ataxia, recumbency, hypersalivation, and sunken eyes. A histological diagnosis of ethylene glycol toxicosis, based on numerous birefringent crystals in renal tubules, was supported by toxicologic findings.