May 12, 2009

Facial Eczema (FE). Farmer Information. Part 13. (Dairy cattle). Zinc sulphate. Direct addition to trough.

Northumberland, farming, animal husbandry, animal health, disease, Facial Eczema, prevention, dairy cattle, zinc, zinc suplphate, direct addition to trough

By Dr Clive Dalton

Original 1991 information written by Dr Barry Smith and Dr Neale Towers, Ruakura Agricultural Research Station, Hamilton, New Zealand.

13. Facial Eczema: (Dairy cattle). Zinc sulphate.  Direct addition to trough.

Direct Addition to Trough
  • Direct addition of zinc sulphate to the trough in the paddock may be undertaken when small numbers of animals are involved such as on small "life style" blocks and the average water consumed daily by the animals is less than two-thirds of the trough volume.
  •  Adding zinc to the water trough is only suitable for protecting cattle - sheep don't drink enough water to ensure zinc intakes are high enough to give adequate protection. Dose sheep with zinc oxide.
  •  Start early so that you can measure daily water intakes and introduce the zinc sulphate gradually before conditions become dangerous.
  •  If spore counts are already dangerous or weather conditions favour fungal growth and rapid increases in spore counts, the troughs should be primed with zinc sulphate to bring the zinc concentrations up to the necessary level immediately.

Priming the troughs
  • Add 0.75 g zinc sulphate for every litre of trough volume (use 0.5 g/litre if using zinc sulphate monohydrate).
  •  Example: for 400 litre trough add 300 g zinc sulphate.
  •  Tie off ballcock, stir to dissolve zinc sulphate.
  •  Remember to prime all troughs before use, e.g. when moving stock to new paddock.
Daily maintenance
Calculate the amount of zinc sulphate to be added to the trough each day.
  • Multiply the dose rate for each class of livestock (Table 1) by the number of animals and total these figures.

  • How much zinc sulphate would a 4 ha block with 2 suckling cows, 4 Friesian yearlings and 4 Friesian calves need each day?
2 F x J cows x 32 = 64g
4 F yearlings x 22 = 88g
4 F calves x 15 = 60g
Total = 212 g per day

  • Add the zinc sulphate to the water trough and stir to dissolve.
  •  Keep the ballcock tied off to prevent dilution of the zinc sulphate solution.
  •  Refill the trough next day and add a further day's zinc sulphate.
  •  Where the water pressure is low and trough refilling is slow the water supply can be left connected. There will be greater variation in zinc concentrations and intakes but good protection should still be obtained.
  •  Where the cattle drink only a small part of the trough content each day replenishing the zinc and refilling the trough can be done less frequently than daily.
  •  Multiply the daily zinc sulphate requirement by the number of days since the trough was last filled.
  •  Add this amount of zinc sulphate and refill the trough.
  •  Tie off the ballcock again until the next refilling.

This material is provided in good faith for information purposes only, and the author does not accept any liability to any person for actions taken as a result of the information or advice (or the use of such information or advice) provided in these pages.

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