Fluoroacetate toxicity protection in cattle

Summary

1. Cattle inoculated with a mixture of bacteria were colonised by strains OR85, 149/33, OB291 and S2/10 at >106 cells/ml rumen fluid. The recombinant strains 0/10, 10/1 and OB156 were rarely detected within rumen contents.

2. All cattle challenged with 0.33 mg/kg body weight of sodium monofluoroacetate, administered in three identical sub-doses at times 0, 3, and 6 h, showed no toxicity symptoms before 6 h, and only mild symptoms before 9 h.

3. Five control animals showed acute symptoms of toxicity, were judged to be unrecoverably intoxicated (recumbent and showing violent neurological signs), and were euthanased at approximately 11 h, 13 h, 15, 15:15 h and 15:30 h.

4. The remaining five control animals showed reduced movement and reduction in rumination during the period 6 h to 20 h.

5. All of the ten test animals showed some reduction in activity, during the period from 9 h to 15 h, but continued to ruminate at a normal level.

6. None of the test animals showed acute symptoms of toxicity.