During the fall of 1989, an episode of equine leukoencephalomalacia involved 18 of 66 purebred Arabian horses at a breeding/training stable in Arizona. Of the 18 horses affected, the condition was fatal in 14. These horses, as well as 48 unaffected horses, had been fed a diet containing a substantial amount of white corn screenings. Gross pathologic findings included liquefactive necrosis in parts of the cerebral white matter and hemorrhagic foci of various sizes in the brain stem. Histopathologic findings included rarefied white matter with pyknotic nuclei and eosinophilic cytoplasm. Thin-layer chromatography, high-performance liquid chromatography, and gas chromatography/mass spectroscopy were utilized to identify and quantitate fumonisin B1 in 3 samples of corn from the farm. Concentrations of fumonisin B1 range from 37 to 122 ppm. Fumonisin B2 was also detected. Using information on diet, animal weights, and feeding practices, estimates of total fumonisin B1 dosage were determined. This is the first definitive report on equine leukoencephalomalacia and associated fumonisin B1 concentrations.

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Three female sika deer from a single captive herd were submitted for postmortem examination over a 139-day period. The first 2 deer submitted were reported to have lost body mass for 20 days to 1 month before euthanasia. One of these deer had diarrhea, the other had a crusting dermatitis on the nasal planum and inner aspects of both pinnae. The third hind did not have any signs of disease before it was found seizuring and was immediately euthanatized. Microscopically, all 3 animals had a lymphocytic vasculitis typical of malignant catarrhal fever (MCF), with the most severe lesions in the brain. All 3 deer were polymerase chain reaction (PCR) positive for caprine herpesvirus 2 (CpHV-2) and were negative for ovine herpesvirus 2 (OHV-2). Two healthy goats that were housed adjacent to the deer were also PCR positive for CpHV-2 and PCR negative for OHV-2. The CpHV-2, PCR amplicons from the hinds, and the 2 healthy goats had an identical single base polymorphism. A male sika deer that was housed with the hinds and a fawn from 1 of the hinds remained asymptomatic and were PCR negative for CpHV-2. This represents the first report of mortality with MCF-like lesions in association with CpHV-2.

Monensin was fed at 0 and 33 ppm in a crossover trial designed to determine the effect of this compound on ruminal and postruminal utilization of a corn-based diet and bacterial protein synthesis in abomasally fistulated steers. Monensin decreased (P greater than .10) ruminal true digestion of organic matter (OMc, corrected for bacterial cell synthesis) and apparent ruminal digestion of starch by 19%, but had not effect on apparent total tract digestion of OM or starch. Apparent ruminal and total tract digestibilities of crude protein (CP) were unchanged. Monensin decreased (P greater than .07) the contribution of bacterial N to total abomasal N (52 vs 58%), and increased (P greater than .06) the contribution of ruminally undegraded feed N (46 vs 40%), but had not effect on total N or amino acids recovered from the abomasum. Efficiency of bacterial protein synthesis (grams bacterial CP/100 g ruminally digested OMc) was unchanged. Monensin decreased (P greater than .05) the fraction of bacterial N to total N digested postruminally (42 vs 50%) and increased (P greater than .05) the contribution of ruminally undegraded feed N digested postruminally (58 vs 50%). Monensin caused a greater proportion of feed N and starch to be digested in the intestines than in the rumen (with possibly greater resultant metabolic efficiency), and this may account for some of the benefits obtained from feeding this compound with high grain diets.

Canine distemper virus has been isolated in dog lymphocyte cultures from the brains of three javelinas that became moribund with signs of encephalitis. Canine distemper viral antigen was demonstrated predominantly in neurons and morbillivirus-like structures were seen by electron microscopy in brains of diseased animals. Serological studies suggest that CDV infection may be common in javelinas.