• Acute toxic plant estimation in grazing sheep ingesta and feces

      Cid, M. S.; Lopez, T. A.; Yagueddu, C.; Brizuela, M. A. (Society for Range Management, 2003-07-01)
      'Romerillo' (Baccharis coridifolia DC), 'duraznillo negro' (Cestrum parqui L'Hérit.), and 'sunchillo' (Wedelia glauca (Ort.) Hoff.) are highly toxic species producing important economic losses of livestock in Argentina. This study assessed the accuracy and precision in the estimation of the percentage and the mass of these species in the ingesta and feces of sheep experimentally poisoned. This study also evaluated whether the quantified percentage and the calculated mass of each toxic species in the rumen+reticulum, the easiest region to sample, are good estimates of their relative consumption. Results indicate that if species fragment density is quantified, and the percentages of non recognized fragments of the toxic species in their in vitro digestion residues are accounted for (attributing some proportion of the unidentified fragment pool to the target species), estimations are accurate, but their precision differ among species. For a 3 sheep sample, the average mass estimated by microhistological analysis represented 92.3 +/- 5.8 (romerillo), 96.5 +/- 17.3 (duraznillo negro), and 92.0 +/- 12.5% (sunchillo) (P < 0.10) of the actual amount of each species consumed. The percentages of the toxic species in the total ingesta plus feces produced since the intoxication did not differ (P > 0.05) from those in the rumen+reticulum. For the evaluated species, the microhistological analysis of the rumen+reticulum not only confirmed the ingestion of the toxic species, but also adequately estimated the percentage in which they were ingested.
    • Microhistological analysis of sheep gastro-intestinal content to confirm poisonous plant ingestion

      Yagueddu, C.; Cid, M. S.; Lopez, T. (Society for Range Management, 1998-11-01)
      The epidermal remains of 4 poisonous plant species that produce acute intoxication in ruminants were quantified by microhistological analysis in the gastro-intestinal content of sheep experimentally poisoned. These species were 'romerillo' or 'mio mio' (Baccharis coridifolia DC); 'duraznillo negro' (Cestrum parqui L'Hérit.); 'poison hemlock' (Conium maculatum L.), and 'sunchillo' (Wedelia glauca (Ort.) Hoff.). All of these species produce important economic losses of livestock in the Flooding Pampa, Buenos Aires, Argentina. The plants used for intoxication were at the vegetative stage of growth. Results indicate that the microhistological technique can be used to confirm the diagnosis of ruminant 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 the digestive tract to confirm romerillo and sunchillo ingestion, because their fragments tend to concentrate there. The uniformity of duraznillo negro fragment distribution would allow identification of this species from any section of the digestive tract. However, the considerable variability in fragment distribution found among animals poisoned with the same plant species makes it necessary to sample more than 1 digestive region if only 1 animal is available for necropsy.