Effective delivery of zinc aids the fight against facial eczema

Moist and warm conditions favour a rise in toxic fungal spores that grow at the base of pasture, often causing facial eczema in cows. This troublesome disease causes liver damage and can lead to lowered milk production and even the death of the animal.

The spores of the fungus Pithomyces chartarum grow on dead matter at the base of the pasture sward, causing numerous problems once cows ingest them. The resulting health issues can be serious and it is estimated that for every clinical case, there are up to 10 that are sub-clinical.¹

The amount of elemental zinc needed is based on the liveweight of the animal. Underdosing can lead to insufficient protection while overdosing can lead to toxicity. To maintain sufficient protective blood serum levels, it is necessary to deliver elemental zinc at 20 milligrams (mg) per kilogram of liveweight per day.² Zinc can be delivered through either feed or water.

Zinc oxide in feed

» The amount of zinc included will be according to a specified feeding rate. It is important to ensure that the amount of feed offered is consistent with the zinc inclusion rate between loads.

» Zinc oxide should be in a pelleted or granulated form when it is mixed with blends. Do not use a powder.

» If you are adding a mineral pellet or granule through a mineral dispenser, ensure it is calibrated for an accurate dose level.

Zinc sulphate in water

» Zinc sulphate can be included in water using a Doseatron or inline water dispenser. The two forms of zinc sulphate are monohydrate and heptahydrate.

» Monohydrate is a fine white powder with a slightly higher elemental zinc level which can be difficult to dissolve. 

» Heptahydrate is a coarse greenish crystal that has a lower elemental zinc level but is easy to dissolve. Be aware it can turn hard in storage.

Either option requires flavouring, such as peppermint, to mask the bitter taste and it allows the water to remain palatable. The inclusion of zinc to water needs to be done gradually over five days to allow the animals to become accustomed to the taste.

Regardless of which method is used, follow the feeding recommendations to ensure the entire herd is protected against facial eczema.

SealesWinslow offers a wide range of zinc solutions and delivery methods from Zincmax+ for adding to water, to high-quality zinc oxide in feed pellets, granulated for adding to a feed blend and mineral pellets to be mixed with grain.

Visit your local PGG Wrightson store for advice on a suitable zinc supplement to assist with managing facial eczema. 

1 DairyNZ. Facial eczema. Retrieved on 17 October 2022 from https://www.dairynz.co.nz/animal/cow-health/facial-eczema/.

2 Dairy Australia. (2013). A review of Facial Eczema: Report of the Dairy Australia Facial Eczema Working Group.