EXPERIMENTAL POISONING OF CATTLE BY THE MUSHROOM RAMARIA-FLAVO-BRUNNESCENS (CLAVARIACEAE) - A STUDY OF THE MORPHOLOGY AND PATHOGENESIS OF LESIONS IN HOOVES, TAIL, HORNS AND TONGUE
Gd. Kommers et Mn. Santos, EXPERIMENTAL POISONING OF CATTLE BY THE MUSHROOM RAMARIA-FLAVO-BRUNNESCENS (CLAVARIACEAE) - A STUDY OF THE MORPHOLOGY AND PATHOGENESIS OF LESIONS IN HOOVES, TAIL, HORNS AND TONGUE, Veterinary and human toxicology, 37(4), 1995, pp. 297-302
Seven 2 to 7-mo-old calves were fed the mushroom Ramaria flavo-brunnes
cens, Clinical signs of toxicosis included salivation, nasal serous di
scharge, smoothing of the dorsum of the tongue, increased sensitivity
in the hooves, reddening of the coronary bands, loss of the long hairs
of the tip of the tail, softening of the base of the horns, and progr
essive weight loss. Affected calves either died or were euthanatized i
n extremis within 12-37 d from the initiation of feeding. Postmortem e
xamination confirmed changes observed in the live calves. Histopatholo
gic changes were marked in those structures where hard keratinization
occurred and there normally is a high uptake of sulfur in the form of
cystine during the keratinization process. Toxicosis appeared to alter
the metabolism of sulfur-containing amino acids in keratinocytes, par
ticularly cystine, with resultant strength loss in the molecular struc
ture of hard keratin and loosening of the hooves, hairs and horns, and
flattening of the lingual filiform papillae.