Sultry Conditions Signal Facial Eczema Risk

The Ministry of Agriculture and Forestry is advising farmers on higher risk farms to take measures to prevent facial eczema. The recent warm humid conditions are likely to mean the start of the main risk period for facial eczema in many districts, especially if the weather conditions continue for several days.

“The warm rain coming down from the sub-tropics is likely to fuel spore count rises over at least the top half of the North Island and possibly also further south,” says Agriquality scientist Tony Fraser. “Counts taken before this rain were already starting to indicate an upward trend, particularly in some parts of Northland, Auckland, Bay of Plenty and Waikato. Serum GGT levels indicate a low level of facial eczema liver damage, although some cases of photosensitivity, probably not due to facial eczema, have been reported from the southern North Island.”

Dr Wayne Ricketts, of MAF Biosecurity Authority’s Animal Welfare Group, says that along with putting preventative measures in place, farmers need to think about how best to deal with those animals which do succumb to the disease, as some inevitably will.

“The Animal Welfare Act requires owners to ensure animals receive treatment that alleviates the pain and distress associated with disease,” he says. “Facial eczema can severely compromise animal welfare.”

The most visible signs of facial eczema are inflammatory, and often infected skin lesions on those parts of the body that have the least protection from hair or wool - typically around the ears, eyes, nose and mouth, the udder, and occasionally the vulva. The lesions cause extreme irritation that can lead animals to rub and scratch. Photosensitivity will also cause affected animals to seek relief in the shade. Any such signs, and stock will immediately need to be moved to toxin-free crops or pasture, or to yards where they can be fed on hay and such supplements as are advised by the local veterinarian.

Dealing with the irritation and skin damage is important. The damage is caused by sunlight so the provision of shade is a must. In a severe outbreak, the ideal action is to put stock in darkened housing, allowing them out at night to graze. The use of natural shade provided by farm vegetation is useful, but in choosing where to place affected stock, farmers need to check spore counts that can be higher in sheltered areas.

Dairy cattle veterinarian, Dr Rochelle Kerr, says covers and zinc-based creams are good for providing protection for the skin lesions. She says cows with affected udders or teats may need to be dried off so as to allow the lesions to heal.

More serious than the skin lesions, is damage to the liver caused by the toxin sporidesmin, a product of the fungus found in affected pasture. “Farmers need to minimise the stresses on their affected animals if they are to return to full productivity,” says Dr Kerr.

“The liver is one of the most important organs in the body, and the damage to it caused by the toxin reduces an animal’s ability to cope with the effects of lactation, pregnancy and parasitism, as well as its resistance to infections. Animals need preferential treatment to aid their recovery,” she says.

Dr Kerr says affected cows - particularly early calvers - should be dried off, and removed from the herd. “They need ad lib access to good quality pasture, and good nutrition is extremely important in aiding recovery, particularly for animals whose systems are already coping with the strains of pregnancy.”

If the available pasture is inadequate, supplements must be fed, while an optimal mineral balance will further reduce stress on these animals. Minimising the effects of parasites by utilising a good drenching programme is also important. Once again, the local veterinarian will be able to advise.

For further information please contact Wayne Ricketts, Animal Welfare Group, MAF Biosecurity Authority Tel: 04 474 4276

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