PATHOLOGY OF NATURAL AND EXPERIMENTAL LEAD POISONING IN CATTLE
2004
Gholami, M.R., Razi Vaccine and Serum Research Institute, Tehran, Iran | Ottaarod, V., Veterinary Organization of Iran, Tehran, Iran | Hablolvarid, M.H., Razi Vaccine and Serum Research Institute, Tehran, Iran | Ezzi, A., Razi Vaccine and Serum Research Institute, Tehran, Iran
Lead poisoning has been recognized in most domesticated animals species (Fenstermacher 1946, Jubb 1985, Link 1966, Allcroft 1951, Radostits 1994, Bywater 1937, Donawick 1966, Zook 1972) and the experimentally induced form has been studied in several species (Hammond 1964, Lampert 1967, Pentchew 1966, Rosenblum 1968, Staple 1955). Lead poisoning in cattle and other species is occurred via oral route or less commonly via the respiratory system or skin (inorganic lead). It affects the CNS, PNS, kidney, liver, bone marrow, bone, gastrointestinal tract, blood, vessels, reproductive and endocrine systems, and seems to acute, subacute or chronic forms (Donald 2002). The common sources of lead are lead bearing paints and metallic lead. After absorption lead is excreted in bile, milk and urine, and the blood levels of lead provide reliable indication of lead status of the animal. Deposition in tissues occurs particularly in liver and renal cortex and medulla in acute poisoning and in the bones in chronic poisoning (Radostits 1994). There is considerable variation between species in their susceptibility to lead and the young animals are more susceptible. Acute lethal single dose for calves is 400- 600mg/kg body weight. Chronic poisoning for cattle is daily dose 6-7mg/kg body weight (equivalent to 100-200mg/kg in the diet (Radoostits 1994). The toxic effects of lead are manifested in three main ways: lead encephalopathy, gastroenteritis, and degeneration of peripheral nerves. The mechanism by which the nervous signs of encephalopathy and the lesions of peripheral nerve degeneration are produced appears to be related to the degenerative changes seen in the nervous tissue (Radostits 1994). Histological tissue changes can be considerable diagnostic value in suspected cases of lead poisoning. Eosinophilic acid fast and intranuclear inclusion bodies with in renal epithelial are pathogonomic for diagnosis of lead poisoning (Zook1969, Donald 2001, Jubb 1985, Jones 1983). In this study the pathology of natural and experimental lead poisoning in cattle was discussed.
显示更多 [+] 显示较少 [-]