Overcome Facial Eczema This Season
What is facial eczema?
Facial Eczema is a devastating disease that causes irreversible liver damage as a result of ingestion of toxic spores from the fungus Pithomyces chartarum. During hot, humid conditions this fungus produces high quantities of the toxin sporidesmin. When ingested for prolonged periods, this toxin interferes with the release of phylloerythrin, a chlorophyll breakdown product. Sheep, cattle, goats and alpaca are all affected by Facial Eczema and can experience significant liver damage, photosensitization, and reddened, shedding skin. While the clinical symptoms are visible, the subclinical effect - liver damage, is concealed and has harmful consequences on animal health. Facial Eczema is to blame for millions of dollars of lost revenue each year. It is responsible for decreased milk yields in dairy cows, poor lambing and calving, decreased weight gains, and reduced animal health. Ultimately if left undiagnosed, the liver damage caused by Facial Eczema can be fatal.
What makes facial eczema so difficult to diagnose?
Facial Eczema causes both clinical (visible) and subclinical (non-visible) symptoms. Only a small percentage of animals (approximately 5%) show clinical symptoms, while the majority of sheep and cattle with facial eczema (approximately 50%) remain undiagnosed and suffer significant liver damage  . Changes in behaviour may be apparent, animals may become distressed, shade seeking, and rub and scratch their skin raw. Liver damage is the most harmful symptom of facial eczema. You can assess liver damage by measuring the proportion of GGT (gamma glutamyl transferase) in the blood. High concentrations of GGT (>700mg/kg) indicate significant liver damage.
Treatment vs. prevention
Unfortunately, once an animal is suffering from Facial Eczema, there is no cure. The main thing you can do is minimise their discomfort. Supply the animal with adequate food, water and shelter. Supplementary feed is recommended. Various forms and concentrations of Zinc are widely used to manage facial eczema. However, Zinc will only aid in neutralising the toxin being taken up, it will not cure the liver damage which has already occurred.
Prevention is the key
Many farms across the country use a range of strategies to minimise the effects of the harmful Pithomyces chartarum spores. Some of these include:
- Pasture treatments with zinc
- Water treatments with zinc
- Supplementary liquid feeds containing zinc
- Changing to pasture types that carry smaller spore loads
- Treatment with a zinc bolus
- Pasture management
- Grazing management
- Breeding for tolerance to facial eczema
Why measure spore counts?
Over the last few years, the combination of humid mild summers, increased irrigation and pockets of rank summer pastures have resulted in dramatic increases in spore challenges in some areas. Typically the North Island of New Zealand has a higher risk of facial eczema compared to the South Island. However, during the warm summer months, high spore levels have been recorded in northern and upper western/eastern regions of the South Island. Consequently, annual trends in spore levels have become difficult to predict.
Environmental factors may affect spore distribution; the degree of shade, pasture species, precipitation, and many other factors. For example, low sheltered areas may have high spore loads while high exposed areas may have low spore loads.
Animal Health Test Packs are used to measure Faecal Spore Counts (FSC), and provide an accurate assessment of spore intake by animals. Spores are not evenly distributed on pasture, therefore FSCs provide us with useful information to gauge the quantity of spores being ingested by the animals as they graze.
Animal Health Test Packs are also used to measure Pasture Spore Counts (PSC) to monitor the contamination level on your property. This information is particularly important when moving animals to un-grazed pasture, to ensure adequate zinc cover is also provided.
Carrying out FSC and PSC is incredibly easy and the results can be used to make informed decisions during periods where spore loads are high. SPORPAK allows you to collect meaningful data which can be used to create appropriate management strategies.