MICROHISTOLOGICAL ANALYSIS OF SHEEP GASTROINTESTINAL CONTENT TO CONFIRM POISONOUS PLANT INGESTION

The epidermal remains of 4 poisonous plant species that produce acute intoxication in ruminants were quantified by microhistological analysi s in the gastro-intestinal content of sheep experimentally poisoned. T hese species were 'romerillo' or 'mio mio' (Baccharis coridifolia DC); 'duraznillo negro' (Cestrum parqui L'Herit.); 'poison hemlock' (Coniu m maculatum L.), and 'sunchillo' (Wedelia glauca (Ort.) Hoff.), All of these species produce important economic losses of livestock in the F looding Pampa, Buenos Aires, Argentina. The plants used for intoxicati on were at the vegetative stage of growth, Results indicate that the m icrohistological technique can be used to confirm the diagnosis of rum inant intoxication by duraznillo negro, romerillo, and sunchillo, but not by poison hemlock because digestion degrades its fragments beyond recognition, It would be convenient to sample the final sections of th e digestive tract to confirm romerillo and sunchillo ingestion, becaus e their fragments tend to concentrate there. The uniformity of durazni llo negro fragment distribution would allow identification of this spe cies from any section of the digestive tract, However, the considerabl e variability in fragment distribution found among animals poisoned wi th the same plant species makes it necessary to sample more than 1 dig estive region if only 1 animal is available for necropsy.