Northumberland, farming, animal husbandry, animal health, disease, Facial Eczema, prevention, dairy cattle, zinc, zinc suplphate, using in-trough dispensers, examples
By Dr Clive Dalton
Original 1991 information written by Dr Barry Smith and Dr Neale Towers, Ruakura Agricultural Research Station, Hamilton, New Zealand.
14. FACIAL ECZEMA: (Dairy cattle). Zinc sulphate. Using in-trough dispensers.
- The use of in-trough dispensers will reduce some of the problems caused by the direct addition of zinc sulphate to the trough.
- These devices still permit variations in concentration of zinc in the trough and the units may need twice-daily attention.
- By comparison, the in-line methods cause smaller and more acceptable variations in zinc concentration and consumption.
- They are more convenient, requiring at most only a brief daily attendance at the one supply point.
- However, for the smaller herd, the dispensers have been refined and can give acceptable results if the makers instructions are followed.
- They are much cheaper devices, but less convenient than in-line methods.
- Calculate the amount of zinc sulphate to be added to the trough daily.
- Multiply the dose rate for each class of livestock (see table) 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
- If attending the trough twice daily (preferred method for in-trough dispensers) add half the daily amount on each visit to the trough.
- In-trough dispensers rely on the turbulence recreated by rapid inflows of water when the ballcock operates to ensure mixing of the zinc sulphate throughout the trough.
- Where flow rates are low occasional stirring of the trough will give better mixing and more even zinc intakes by all cows.
- Use the dispenser according to manufacturers’ directions.
- There are two forms of zinc sulphate available.
- Zinc sulphate heptahydrate is the material commonly available.
- Zinc sulphate monohydrate is now also being sold; this is a more concentrated form of zinc sulphate and is used at two-thirds the dose rates used for the heptahydrate.
- Once calibrated, a volumetric measure is sufficiently accurate for regular use.
- Weigh out the required zinc sulphate into a plastic bucket. Level the surface and mark the height.
- Fill the bucket to this level each day.
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.