The Facts on Facial Eczema

Facial Eczema (FE) is caused by a toxin sporidesmin produced by a pasture fungus Pithomyces Chartarum which thrives in warm moist conditions, found mostly in rye grass dominant pastures. This toxin is ingested by animals grazing affected pasture.

Symptoms

The period between spore ingestion and first symptoms depends on the amount of toxic spores actually consumed but can occur within 24 hours.

Affected animals are likely to:

• Go off their feed
• Stop milking
• Become restless
• Seek shade
• Start licking, rubbing and scratching affected areas 

After a few weeks:

• Skin lesions start to appear around the face, nostrils, ears, teats, vulva, and on any white areas
• Skin becomes reddened and inflamed, and may then thicken, encrust, blister and weep
• Liver damage and in severe cases, signs of jaundice may be visible
• Ultimately, cows may dry off completely
• Animals pass into a state of chronic ill-health or in extreme cases die. Others may show no clinical signs at all.

Sub-clinical signs:

• Increased barrenness
• Increased deaths at lambing and calving
• Decreased wool and meat growth
• Depressed milk production

Farmers often attribute these signs to something else. The reality, however is these are signs that stock are suffering from sub-clinical facial eczema. Productivity and income will be significantly affected.

Ideal Conditions

For fungal growth can be as follows:

• Ryegrass dominant pastures
• Dead leaf matter in the base of pasture
• Fairly still, humid weather / some light rain or heavy dews and 2-5 continuous mild nights with pasture temperatures > 13°C.

Factors which determine toxicity level of a pasture depend on:

• Pasture spore counts around 30,000 per gram of pasture cause sub-clinical symptoms and are accumulative
• Counts of >80-100,000 will cause clinical symptoms of FE
• Hard grazing increases the risk of ingesting high volumes of spores
• Previous spore exposure and intakes increases susceptibility

Control and Prevention

Prevention is the only recognised method of dealing with FE, however, no one method is 100% effective.

Pasture management

• Hard graze paddocks to reduce amounts of rank, dead pasture material prior to the FE season
• Avoid topping paddocks in late Summer/Autumn which will increase the amount of dead leaf matter present
• Monitor climatic conditions and on-farm spore counts so you know the risk. District trends are certainly useful but indicative only
• Identify your highest risk areas and if possible avoid animals grazing them

Animal management

• Zinc oxide (80% elemental zinc) daily by drench
• Zinc oxide via a controlled release The Time Capsule bolus that allows a consistent daily dose of zinc to be released into the rumen. The Time Capsule provides reliable protection for 4-5 weeks in cattle and 6 weeks in sheep
• Zinc sulphate in drinking water in combination with flavouring eg Grapple, to disguise the taste.
• Feed Zinmol, an Agri-feeds molasses based complementary liquid feed containing 1.2% elemental zinc