Facial Eczema

Facial Eczema can affect dairy and beef cattle of all ages but younger animals are more susceptible.

Symptoms of the Disease/Condition. 

Facial eczema (FE) can be a very important disease in certain parts of NZ where the summer/autumn climate tends to be warm and humid.

• Sheep are most susceptible followed by dairy cattle, beef cattle, and red deer.
• Animals get FE after eating large numbers of fungal spores (Pithomyces chartarum) which contain the toxin sporidesmin.
• Sporidesmin causes liver damage which can then lead to photosensitisation.
• Photosensitivity occurs because the FE damaged liver cannot breakdown grass pigments from grass that the animal has eaten.

FE classical skin lesions are only the tip of the iceberg but are what is seen on the outside. Numerous studies indicate that up to 50% of a mob can have liver damage with only about 3% showing the typical skin lesions.  The real impact comes from the liver damage caused by the sporidesmin.

The effect of FE at the individual farm level is related to both the challenge on the pasture and the ability of the animal to withstand that challenge.

Is Your Current Preventive Programme Working?

Over the past few seasons facial eczema has been a major cost to many sheep and dairy farms. VetEnt investigations have highlighted several factors associated with facial eczema outbreaks.

Unaware of the facial eczema challenge: 

• Starting the preventive programmes too early or ending them too early.  
• Not knowing the level of challenge on different parts of the farm.

Unaware that animals are affected: 

• The obvious skin lesions are only the tip of the iceberg. 
• Only a small proportion of the animals develop skin lesions which appear about 2 weeks after the challenge.

The real cost of facial eczema is associated with the liver damage which can have a significant impact on milk production, cow live weight, dairy heifer growth rates, ewe mating performance and lamb growth rates even when there are no signs of skin lesions.

Cows not getting enough zinc:

• Under-dosing due to under-estimating cow liveweights, inaccurate mixing and dosing, using low quality zinc products.

Mycotak not being used correctly:

• Mycotak must be applied with Mycowet onto pastures that are green and growing and have spore counts less than 15-20,000.

Understand the Disease Better.

Our philosophy is “the more our clients understand their risks, the more successful their risk management”.

Some of our knowledge has come from our own research and investigations which often contradicts quite a few very old, established myths about facial eczema and its management.

Management plan includes:

• Planning for prevention.
• Applying fungicides.
• Selling susceptible animals.       
• Grazing "safer" pastures.
• Zinc treatments.

What’s Happening in Your Animals?

Our research suggests a trigger point when liver damage is likely to affect ewe mating performance and tolerance to facial eczema varies widely between flocks. We can use blood tests to get an indication of the tolerance status of your flock which will help to provide a cost benefit analysis for whole flock treatment with zinc capsules.

Cost/Impact on Herd/Farm Revenue

It is the sub-clinical (not easily seen) disease that has the major impact on farm business performance.

The subclinical effects of FE in cattle include:

• Weight loss & decreased weight gain- important with young dairy grazers, early weaned beef calves, or 16-18 month old grazing and beef cattle.
• Lower milk production soon after cattle take in toxic spores.

FE is best diagnosed by a blood test to measure GGT in live animals.  GGT is an enzyme released into the bloodstream from the damaged liver cells.  It is NOT specific for FE.

Management and Control.

There is no effective treatment for the liver once it has been damaged. However, the liver does have a huge capacity to recover itself as long as the damage has not been too extensive.

Shelter is important for relief from the sun in animals showing clinical signs.

To manage the risks associated with FE we need to understand the fungus which lives in the pasture and the animals that are grazing that pasture and the farm itself.

There is a wide range of products for use to prevent liver damage in animals and reduce spores on the pasture. Timing of the treatments is critical so pasture spore count monitoring is essential to get the best return from the FE management investment.