“Face Off” Facial Eczema– Don’t get caught out this season.
This is one of the most unsightly, painful and debilitating conditions seen mainly in cattle, sheep and alpacas. It is also one of the most preventable.
The fungus Pithomyces chartarum lives in the base of the grass all year round. In the heat of summer, the grass goes into its reproductive phase and a lot of dead matter is produced which falls to the base of the sward. When the rain arrives in mid-late summer (and early autumn), the fungus uses the dead matter, warmth and moisture to grow and reproduce. Spores are released into the air and land on nearby grass to germinate. Animals eat these microscopic spores while grazing. A liquid contained inside the spores called sporidesmin leaches out into the animal’s gut and the liver attempts to excrete it as a waste product. In the process, free radicals are produced and the liver is damaged. The bile ducts are most severely affected.
As the animal grazes, a compound in grass known as phyloerythrin is usually excreted though the bile ducts. This is no longer possible due to the liver damage. The phyloerythrin therefore circulates in the blood stream and when it enters the skin, the sunlight reacts with it and causes severe sunburn (photosensitization). This effect is much greater on pink skin.
The sunburn is what we see, usually as blistering and peeling of the skin and can be very severe in some cases. It is important to remember, though, that the effects on the skin are only indicators of the liver damage. All-black animals can have severe liver damage despite normal looking skin.
Blood tests can be done to assess the degree of liver damage and severely affected animals will be jaundiced (yellow gums). In these cases, death is not uncommon. Affected animals can benefit from antibiotics to prevent secondary infections and anti-inflammatory steroids to reduce the irritation. They should also be kept out of the sun and good fly control is essential. A topical cream can be used to provide some UV protection. Easy access to high energy food is important as is providing water in the shade so the animal doesn’t have to enter sunlight to drink.
PREVENTION IS THE KEY.
Spore counts tell us how high the risk of FE occurring is. Bring us a large ziplock bag full of grass (down to soil level) from different paddocks (and different areas of different paddocks) every week or two in FE season. When the spore count increases, it is time to start zinc supplementation. Alpacas are the most susceptible and very low levels of spores can cause severe disease so pre-emptive supplementation is often a good idea.
Zinc binds to sporidesmin and prevents the liver damage from occurring. Animals need a daily oral zinc supplement in the facial eczema risk period to prevent it. This can be in the form of zinc sulphate in the water, zinc boluses (release zinc into gut daily for 4-6 weeks), or feed pellets containing zinc- often used in alpacas. Each form of supplementation has its pros and cons so please have a chat with us about the best option for you.
Not every property is at the same risk of developing facial eczema due to differences in grass species, paddock contour and management systems. Every season is different also with regards to the prevalence of FE and time of onset so if you haven’t had it before, it doesn’t mean you won’t get it. This is why spore counts are the best way to monitor the risk to your animals.