Pathology of chronic paraquat toxicity in calves

Paraquat (1–1’ dimethyl 4–4’ bipyridylium) was administered orally @ 2 and 4 mg/kg body weight to the group I and II (3 calves in each group), respectively for 90 days. Group III was kept as control (3 calves). Notable clinical signs i.e. frequent urination, frothy salivation, lacrimation, muscular tremor; blind staggers, convulsion and coma were recorded. Gross and microscopic lesions after death or sacrifice were observed in the lung, liver, kidney, heart, brain, small intestine, abomasum, spleen, salivary and thyroid glands. The lesions showed varying degrees of congestion and haemorrhage in the organs. Proliferation of fibrous connective tissue in the interstitial spaces of lungs and kidneys, proliferation of bile-duct epithelium and bronchial epithelium and chronic glomerular nephritis were the significant lesions of chronic paraquat toxicity. Collected blood and serum samples showed various results of Hb, TLC, DLC, SGOT, serum creatinine, BUN serum protein which are indicative of the state of liver and kidneys during chronic PDCL toxicity. Chronic doses of paraquat even with low dose @ 2 mg/kg body weight affect all the vital organs in calves.