Matamata Veterinary Services | Latest News

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Nitrate Poisoning Alert

May 17, 2017

A case of nitrate poisoning was seen today where one cow died and four cows had to be treated.

This classic case involved the following:

  • Cows hungry – previous break was grazed down to 1000-1200 KgDM/Ha
  • Annual ryegrass at 2800 KgDM/Ha, therefore raidly growing after previously having been nipped off by young stock
  • Urea applied 7 days previously
  • Grey, overcast day. Rapid growth recently, therefore leading to a build up of nitrate in the plant
  • Hungry cows consumed high nitrate content grass in a short period of time.



  1. Avoid hungry cows going onto potentially dangerous pasture. Rapid intake of even moderately dangerous grass can cause problems. In contrast, cattle grazed ad-lib on high nitrate content grass, when they are constantly full, will be less likely to have toxicity issues.
  2. Have pasture tested for nitrate content prior to grazing.
  3. Keep a close eye on cows after grazing (usually 4-6 hours after intake).


For advice on your farm’s situation, to order and on-farm nitrate test kit, or if you would like to bring in a sample for one of our staff to check the level for you, please phone the clinic on 07 888 8197.