By Dr Clive Dalton
Original 1991 information written by Dr Barry Smith and Dr Neale Towers, Ruakura Agricultural Research Station, Hamilton, New Zealand.
Part 7. Facial Eczema. Zinc Oxide. Motor-driven drenching systems
Some motor-driven drenching systems cannot be adjusted to the recommended dose volumes. Therefore the drench mixture must be adjusted so that the correct amount of zinc oxide is given.
Establish the drench volume/cow.
- Deliver a set number of shots into a measuring jug.
- Record the total volume.
- Divide the total volume by the number of shots to get the shot volume.
- e.g. 10 shots equals 550 ml
- Shot volume = 550 +- 10 = 55 ml
- Repeat at least once to confirm the result.
Note. These rates give the same zinc dose as the other zinc drenches.
These rates are higher than recommended in AgLink FPP 496.
- Subtract 3 ml from drench shot volume to compensate for the volume of the zinc oxide, e.g. 55 ml - 3 = 52 ml.
- Multiply volume and the zinc oxide dose rate by the number of cows, e.g. 100 cows x (10 g zinc oxide + 52 ml water) = 1 kg zinc oxide + 5.2 litres water (1 kg + 5 litres rounded off).
- Multiply the daily mix by the number of days, e.g. for 20 days = 20 kg zinc oxide + 100 litres water.
- Most farmers would prepare a bulk mix of a 20 kg bag of zinc oxide.
have not been overdosing.
- e.g. 100 cows (J x F) @ 10 g/day for 50 days = 100 x 10 g x 50 days = 50 000 g (50 kg).
- Have you used more or less than 50 kg zinc oxide so far?
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.