Fate of Banvel T, Ioxynil, Tordon, and Trifluorilin in the Dairy Cow

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Abstract
Banvel T, ioxynil, Tordon, and trifluorilin herbicides were fed (5 ppm. ) to catheterized lactating cows. No residues of Banvel T, ioxynil or trifluorilin were found in the milk. Banvel T and Tordon were eliminated (89. 4 and 97. 7%, respectively) intact in the urine. No ioxynil or 3, 5-diiodo-4-hydroxybenzoic acid (a possible metabolite) was found in the milk, urine, or feces. Elimination of equivalent ioxynil in the urine based on neutron activation analysis of total iodine was 123%. Hydrolysis of urine revealed a possible conjugated phenol metabolite of ioxynil. Its retention time was identical to a peak produced by partial sodium reduction of ioxynil or by exposure of ioxynil to strong ultraviolet light. The metabolite may therefore have been 3-iodo-4-hydroxy-ben-zonitrile. Trifluorilin was not found in the urine. Trifluorilin completely disappeared (while ioxynil remained stable) during 24 hours in an artificial rumen, possibly by nitro reduction.