News & Advice

How much Zinc is your herd really getting?

Mar 1, 2017 | Dairy, Dairy Animal Health & Welfare, Minerals

Last summer, spore counts were excessively high causing wide spread Facial Eczema outbreaks across the Waikato. Ensuring adequate Zinc supplementation is key to prevention. We have already tested herds this season by checking blood Zinc levels, and this has shown a wide range of levels even when full dosing has been provided.

The protective range for Zinc levels in the blood is above 18umol/L. Anything under that is likely to be ineffective and your herd could suffer liver damage, causing further problems throughout the year. Some herds have had up to 80% of their cows with inadequate levels. We have intervened and modified the dosing accordingly to ensure protective levels are met. Unfortunately, this is commonly seen with Zinc dosing, particularly when Zinc is provided through water treatment. We have also seen inadequate Zinc levels in herds that drench with Zinc oxide as well.

Water intake depends on rainfall and individual cow risk factors like age, milk production, ‘pecking order’ in the herd and walking distances, so water based Zinc supplementation becomes quite unpredictable.

If you are using water treated with Zinc to protect your cows against Facial Eczema, it is best to check your Zinc levels two to three weeks after you start full Zinc dose rates. Call your Vet to arrange blood samples to be taken from your cows to check they are getting enough. Last season was a terrible year for Facial Eczema and we don’t want it to happen again! 


9 things to check if you are using water treated with Zinc to protect your cows against Facial Eczema:


  • Try to make sure that your cows don’t have access to untreated (no Zinc added) water.
  • Make sure there are no water leaks.
  • Use a flavour like aniseed, caramello or apple to encourage the cows to drink the Zinc treated water.
  • Check the weight of your cows and the product you are using and work out a dose rate – your Vet can help.
  • Measure the amount of Zinc you are adding every time you add it- no guesstimates!
  • Dose the cows daily.
  • Start your Zinc water trough treatment early to ‘prime your troughs’ before Facial Eczema season.
  • Start the cows on a half dose of Zinc to ‘prime’ your troughs and get cows used to the taste of Zinc
  • If you have ‘missed the boat’ you can prime your untreated water troughs now – talk to your Vet about how best to do this.
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