Poisoning of cattle by amaranthus

Extract

Sir, — The July issue of the journal contained a letter on the above subject that caught my attention. It seems that the author is unaware of reports of poisoning by redroot in New Zealand and I thought it appropriate to draw his attention to them. Brackenridge (1956 Brackenridge, D. T. 1956. Nitrate poisoning caused by turnips and red-root. N.Z. vet. J., 4: 165–166.  [Google Scholar]) reported an outbreak of nitrate poisoning in cattle grazing redroot and turnip tops and the following year Coup and I published on poisoning by these two plants and green oats. We also reported experimental poisoning of three cows with red root. Duckworth's findings are similar to those reported in previous outbreaks. As I recall, in the 9 years I was in the diagnostic section at Ruakura, these were the only recorded cases of nitrate poisoning in cattle. The infrequency of redroot poisoning may be a reflection of the small chance that all the conditions necessary to induce it rarely occur at the same time.