THERAPEUTIC EFFICACY OF METHYLENE-BLUE IN ACUTE EXPERIMENTAL NITRITE POISONING IN BUFFALO CALVES

Nitrate/Nitrite poisoning is common in countries where nitrate rich fe rtilizers are abundantly used to improve the yield of cereals and fodd er crops. However, in India a few cases of nitrate posionsing have bee n reported (Prasad et al., 1983). Nitrate rich plants are mojor source of poisoning characterized by methamoglobinaemia, In reuminants after ingestion of nitrate rich plants, nitrate is rapidly reduced to ammon ia through nitrite and hydroxlyamine in the rumen but excess intake fa vours the production of high levels of nitrite and hydroxlylamine whic h are rapidly absorbed into the ciruclation where they oxidise haemogl obin to methaemoglobin. Excess formation of methaemoglobin causes sudd en death of animals due to anoxia if appropriate therapy is not given in time (O'Hara and Fraser 1975). Methylene blue is widely accepted as an antidote to the treatment of nitrate/nitrite intoxication in anima ls (Burrow, 1984; Bhikane et al., 1990). Over zealous use of methulene blue may lead to formation of additional methaemoglobin (Kirti Dua an d Prasad, 1985). An attempt has been made to evaluate the efficacy of methylene blue against acute experimental nitrate poisoning in buffalo calves.