Facial Eczema (FE). Part 5. Farm Information.(Dairy Cattle). Zinc oxide. Long-term dosing.

Agriculture, Farming, animal husbandry, animal health, disease, Facial Eczema, advice on prevention, recommendations, zinc, zinc oxide, long-term dosing, recipes.

By Dr Clive Dalton

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

5. Facial Eczema: (Dairy Cattle). Zinc oxide. Long-term dosing.

• Milking cattle are best dosed daily, this gives best protection and, once the cows are trained, causes less disruption in the shed.
• Milking cattle can be protected by dosing at 2 or 3 day intervals. Do not dose at greater than 3-day intervals as the high zinc doses will cause milk fever in a small proportion of the cows.
• Dry cattle can be dosed twice weekly, or at weekly or fortnightly intervals.
• Dose rates need to be increased to account for less efficient protection and the length of interval between doses if not dosed daily.
• Zinc oxide dosing can be expected to markedly reduce, but not totally prevent, FE outbreaks.
• Daily dosing should reduce the number of animals affected and the severity of the damage to the livers of affected animals by 80-90%.
• Twice-weekly (lactating) and weekly dosing (dry stock) by 70-80%.
• A more stable and concentrated drench can be made by including either a commercial stabiliser such as CoZinc (Coast Biologicals Ltd) or Maximix (Bell-Booth Ltd), or a liquid "farm" strength seaweed fertiliser such as Maxicrop (Bell-Booth Ltd), Green Label Response (Coast Biologicals Ltd) or Sea Magic (Yates Ltd).

Remember: Not all liquid fertilisers are seaweed based.

• Stabilisers have two advantages:
• (1). They increase the ease of mixing and drenching.
• (2). They allow the mixing of more concentrated drenches and therefore use of smaller drench volumes.
• Make sure you use the right dose rate for the type of drench mixed.

Note: Proprietary mixes such as Cozinc (Coast Biologicals Ltd), Maximix (Bell-Booth Ltd) and Nu Zinc (Nufarm Ltd) should be mixed and used as recommended on the product label.

Recipes
Unstabilised drench

• Mix 1 kg zinc oxide with 2.5 litres of water.
• Sprinkle powder on water and leave to wet.
• Stir until smooth and lump free.
• If too stiff to flow through drench gun, add a little more water.
• If too thin to stay in suspension, stir in a little more zinc oxide powder.
• This produces about 2.7 litres of drench.

• Daily dosing: 7 ml/100 kg liveweight.
• 3-day, weekly: 10 ml/100 kg liveweight x No. of days between drenches

Stabilised drench

• Mix 1 kg zinc oxide powder with 1 litre of water and 200 ml of "stabiliser".
• Mix the stabiliser and water first.
• Sprinkle powder on the water and let settle and wet.
• Stir to a smooth creamy paste.

• Daily dosing: 3.6 ml/100 kg liveweight.
• 3-day-weekly: 5ml/100 kg liveweight x No. of days between drenches.

Disclaimer
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.

Facial Eczema (FE). Farm Information. Part 4.Zinc oxide. General dosing information.

Agriculture, farming, animal husbandry, animal health, disease, Facial Eczema, prevention, zinc oxide, general dosing information, zinc, toxicity, copper, selenium

 By Dr Clive Dalton

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

4. FACIAL ECZEMA:  Zinc oxide. General dosing information.  

When to Start

•  Have supplies of Zinc Oxide and the equipment needed ready well before the FE season starts. Supplies can be difficult to buy during an FE outbreak.
•  Zinc dosing should begin as soon as the weather conditions (warm, humid, grass minimum temperature more than 13"C, heavy dew or 3-4 mm rain) favour spore growth and/or at the first signs that spore counts are beginning to rise. Don't wait until dangerous conditions arise, or until clinical cases are seen. 
• The spore rises precede clinical symptoms by some 10-1 4 days, and to be effective zinc must be dosed before or at the time the animals graze toxic pasture. 
• Farmers regularly monitoring spore counts early in the season could delay starting dosing until counts begin to rise (don't wait until they reach danger level). It usually takes more than a week for the earliest spore rise of a season to reach danger levels, so starting dosing immediately spore rises begin should provide adequate protection.
• On problem farms in particular begin dosing in mid-January and continue throughout the autumn. 
• Stock should not be exposed to zinc unnecessarily and excessively prolonged zinc dosing lowers the safety margin.
  

How to Start

• Begin dosing at long-term dose rates unless dangerous conditions already exist.
•  If conditions become dangerous during the first week of dosing increase the dose rate to "crisis" levels. Keep dose rates at this level for two weeks then reduce to long-term dose rates.
  

When to Stop

• Continue dosing through the expected FE season.
•  Towards the end of the FE season dosing can stop when spore counts fall to low levels and weather conditions are dry and cool. But watch the weather and start dosing if conditions favour spore growth again.
• After long-term zinc dosing ceases, protection will carry over for several days.
• After prolonged zinc dosing, protection will be quickly re-established once zinc administration begins again.
  

Zinc Toxicity

• Overdosing with zinc is toxic. Take care calculating dose rates, weighing zinc and mixing drenches. Check drench guns for accuracy.
•  There is a 3-fold safety margin for dosing zinc over 60 days, i.e. if three times the recommended rate is given it will cause damage to the pancreas.
• The safety margin for dosing for longer periods is progressively reduced. Hence the need to use the correct dose rates, and avoiding unnecessary dosing for long periods.
• Pancreatic injury must be severe before effects on animal health are noted. The pancreas will recover when zinc dosing ceases.
• Administering zinc oxide drenches in large amounts as may occur with weekly or fortnightly dosing interferes with calcium metabolism (and may cause milk fever) and is not recommended for lactating stock.
• Because elevations of zinc occur in liver and kidney (not meat) a withholding period of 1 week should be allowed before animals are slaughtered.
  

Copper and Selenium

• Long-term zinc dosing may interfere with copper and selenium metabolism, although it has not yet been shown to induce copper or selenium deficiency.
•  In areas where these minerals are deficient supplement the animals with copper and selenium immediately after zinc administration ceases.
• Don't give copper supplements during the FE season unless clinical deficiencies exist. If copper supplements are required use an injectable preparation.
  

Purity of Zinc Compounds

• Ask the supplier if the zinc oxide meets the Animal Remedies Board's specifications.

General
A volumetric measure of the zinc oxide is sufficient when mixing. Weigh out the zinc oxide needed to dose all animals, smooth the surface and mark the surface height on the container. An independent check of calculations should be made and professional advice sought if there is any doubt about the methods.


Disclaimer
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.

Facial Eczema (FE). Farmer Information. Part 9. (Sheep). Zinc oxide. Long-term dosing.

Agriculture, farming, animal husbandry, animal health, disease, Facial Eczema, preventoin, zinc, zinc oxide, dosing, long-term dosing, recipes.

By Dr Clive Dalton

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

9. Facial Eczema: (Sheep). Zinc oxide. Long-term dosing.

• Sheep should be dosed regularly with zinc oxide throughout late summer and autumn period.
• Zinc dosing should start at least 2 weeks before dangerous conditions normally occur. In most districts this means dosing should start in early to mid January.
• Dosing should continue until cooler winter weather conditions occur.
• Protection can be obtained buy dosing twice weekly, or at weekly or fortnightly intervals. However, at the longer dosing intervals lower levesl of protection can be expected.
• Weekly dosing should reduce liver damage by 60-70%.
• Dosing at 2-week intervals will give less protection and reduce liver damage by about half if carried out regularly during the FE season.
• If dosing at 2-week intervals, the next zinc oxide dose should be brought forward if a danger period occurs in the last half of the interval.
• Dosing at 2-week intervals has on occasion been associated with salmonellosis outbreaks. Where this has been a problem, a maximum dosing interval of 1 week is recommended.
• Zinc oxide drenches can be prepared with or without a seaweed “stabliser”.

• Stablisers have two advantages:
• (1). They increase the ease of mixing and drenching.
• (2). They allow the mixing of more concentrated drenches and therefore use smaller drench volumes.
• Recipes and dose rates of both types of drenhches are provided below. Make sure you use the right dose rate for the type of drench mixed.
  

Note: Proprietory mixes such as Cozinc (Coastal Biologicals Ltd), Maximix (Bell-Booth Ltd) and Nu Zinc (Nufarm Ltd) should be mixed and used as recommended on the product label.

Unstabilised drench

Recipe

• Mix 1 kg zinc oxide with 2.5 litres of water.
• Sprinkle powder on water and leave to wet.
• Stir until smooth and lump free.
• If too stiff to flow through drench gun, add a little more water.
• If too thin to stay in suspension, stir in a little more zinc oxide powder
• This produces about 2.7 litres of drench.
  

Stabilised drench
A more stable and concentrated drench can be made by including either a commercial stabiliser such as CoZinc (Coast Biologicals) or Maximix (Bell-Booth Ltd), or a" farm" strength liquid seaweed fertiliser such as Maxicrop (Bell-Booth Ltd), Green Label Response (Coast Biologicals Ltd), Sea Magic (Yates Ltd).

Recipe

• Mix 1 kg zinc oxide with 1 litre of water and 200 ml of "stabiliser".
• Mix the stabiliser and water first.
• Sprinkle powder on the water and let settle and wet.
• Stir to a smooth creamy paste.
• This produces about 1.4 litres of drench.
  

Dose rates:

• Unstabilised - 1 ml/10 kg liveweight x no. of days.
• Stabilised - 0.5 ml/10 kg liveweight x no of days.
  

Approximate dose volumes:

Footnote 2009: Zinc boluses are now available. Contact your veterinarian for information.

Disclaimer
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.

Facial Eczema (FE). Farmer Information. Part 7. Zinc Oxide. Motor-driven Drenching Systems

Agriculture, farming, animal husbandry, animal health, disease, Facial Eczema, advice, recommendations, zinc, zinc oxide, motor driven drenching systems, methods

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.


Method
-
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.
  

Determine the correct zinc oxide dose per cow from the table below.

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.
  

Note: In mid-season, check your zinc supplies and your arithmetic to make sure you
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?
  

Disclaimer
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.