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Facial eczema season – be prepared

Facial eczema is an important disease of cattle, sheep and goats

By Dr. Sue Hides - 15th January 2003 - Back to News

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Facial eczema is an important disease of cattle, sheep and goats, caused by a invisible fungus (Pithomyces chartarum) which grows in dead grass litter that is always present in pasture. The spores of the fungus contain a toxin which, when eaten by stock, causes damage to the liver. Liver damage is responsible for photosensitization (sunburn), production loss and sometimes death.

All farmers should familiarise themselves with monitoring and control procedures. The disease occurs sporadically, in some years multiple farms will be affected, however a small number of farms are affected with facial eczema in most years. The disease can cost a herd or flock thousands of dollars in reduced production

Outbreaks of facial eczema generally occur in late summer and autumn when conditions are suitable for the production of large numbers of fungal spores on pasture. Spores are present in grass litter at the pasture base throughout the year. The fungus grows best when humidity is high and temperatures at ground level are above 12-15oC for a few days. In Gippsland, these conditions are most likely to occur during February to April. However there were two periods in mid and late December 2002 in the Macalister Irrigation District where terrestrial temperatures were suitable for spore growth.

Preventative measures are only of value if applied before cattle graze toxic pasture. By the time signs of facial eczema are apparent, it is too late to implement effective control measures, unless spore numbers remain at toxic levels. There is a lag time of between 10-20 days between eating toxic pasture and the appearance of signs of the disease.

Effective control of facial eczema on a farm can only be achieved if monitoring of spore numbers occurs on that farm. Spore counts vary dramatically from farm to farm and paddock to paddock, according to aspect, elevation, prevailing wind, pasture litter and height. Animal Health staff of the Department of Primary Industries (DPI) will be able to advise you of monitoring procedures that can be undertaken on your farm. Grass samples for spore counting can be delivered to DPI offices at Maffra (ph 51470 800), Leongatha (ph 56 629 900), Bairnsdale (ph 51 520 600) or Ellinbank (ph 56 242 222) for submission to a veterinary laboratory, for a fee of $11 per paddock.

To collect grass samples from the paddock to be monitored, cut a handful of grass one centimetre above ground level using a sharp knife, repeat this procedure at more than 10 places in the paddock about 10 metres apart, place all the sub-samples from the paddock into a single bag and label it with your name and the paddock name.

The chemicals used to control or prevent facial eczema are available, but should be used only under veterinary advice as they can be toxic if not used strictly in accordance with directions or for an extended period of time. These chemicals are not registered stock medicines and can only legally be dispensed under veterinary prescription.

Farmers are advised to start thinking about facial eczema now. Listen and watch for facial eczema warnings during the season, spore test on your own farm in conditions of high temperature and humidity, discuss prevention methods with your veterinarian.

For access to current weather records which may give some indication of the risk of an outbreak call animal health staff at DPI Offices at Maffra, Leongatha, Bairnsdale or Ellinbank. Information pamphlets are also available at these offices.

CAN YOU DO WITHOUT A NUTRIENT BUDGET?

Are you applying enough fertiliser to reach your target nutrient levels? Are you wasting money applying too much fertiliser? Or are you applying fertiliser to some paddocks that don’t need it while others could do with more? Are you over applying one nutrient and mining another?

A nutrient budget enables you to put numerical values on the movement of nutrients on, off and around the farm. You can then tailor accurate fertiliser requirements to different parts of your farm, giving you the comfort of knowing you are applying the right nutrients where they are needed. Nutrient budgets coupled with soil tests will also give you a clear picture of what is happening on your farm over time.

The nutrients that are essential for plant growth such as phosphorus, potassium and sulphur are brought onto the farm in feeds such as grain or hay. Effluent applied to paddocks also provides additional nutrients. Nutrients move off the farm with products that leave the property such as milk, meat or hay. Nutrients are also lost from the farm in runoff, if the runoff is high in nutrients it has the potential to reduce water quality through nutrification, this is a key factor in algal blooms. Careful attention to timing of fertiliser application to avoid periods of water runoff will help to minimise this nutrient loss.

A nutrient budget aims to balance the nutrients that are taken off farm with the nutrients brought onto the farm while taking into consideration the soil factors. By balancing the system, the requirements for production are being met without applying excess nutrients.

There are a number of nutrient budgeting tools available to help you develop a budget and calculate your fertiliser needs. One simple-to-use tool is ‘NutriMatch’, developed by Target10 and the Department of Primary Industry (DPI) using information from the Phosphorus for Dairy Farms trial at DPI Ellinbank. It is available on the Target 10 web site or in booklet form from DPI at Ellinbank. The web address is www.target10.com, NutriMatch can be found in the online consultant under the soils and fertiliser heading.

For more information on developing a nutrient budget using NutriMatch please contact Annette Coster on (03) 5624 2234 or Colin Waters on (03) 5624 2273 or 0419 326993.

IS THAT A FERN ON YOUR DAM?

The surfaces of many local farm dams are sometimes partly or completely covered by a floating native aquatic fern called Azolla. Azolla plants have snow-flake shaped or triangular fronds up to 10mm wide and 30mm long. They may be red or green in colour depending on the amount of sunlight. During spring or in shaded situations the upper parts of the plants are green, whereas in summer and autumn, when exposed to full sunlight, they become dark red. Fine roots up to 4mm long hang in the water below the floating fronds.

Azolla is not harmful to stock that drink the water or consume the plant. Nor does Azolla have a deleterious effect on domestic house and garden water. When Azolla forms extensive surface mats it can adversely affect aquatic life in the dam however, due to the restricted penetration of sunlight and depletion of oxygen. It can also block pipes and pumps, and deter stock from watering.

The fronds are high in protein and nutrient rich, particularly nitrogen, as they contain a nitrogen-fixing blue-green algae. Overseas, Azolla is used as a fertiliser in rice fields and has been used as a feed source for various domestic animals and plants. It has also been scraped off dams and used on vegetable gardens and house gardens as a free fertiliser.

Aquatic plants such as Azolla are important habitat for a range of aquatic life including invertebrates, fish and birds. Azolla may also help to reduce nuisance algal growth by providing refuge for algae grazers, and by reducing the availability of nutrients and light.

If extensive Azolla mats are causing an immediate problem, some can be removed by manually or mechanically scraping the top of the dam. A home-made two-person scraper using fine chicken netting is a cheap, practical method. While there are chemicals registered to kill Azolla, the process may have side effects of directly killing beneficial aquatic life, or indirectly through rapid plant decay leading to oxygen depletion in the dam.

Minimising the amount of available nutrients and sunlight will lower the potential for excessive growth of Azolla, algae and other aquatic plants. Where possible:

  • Reduce fertilisers entering the dam by leaving an unfertilised area around the dam
  • Leave a buffer area or filter area of vegetation above the dam to minimise entry of nutrients and sediments.
  • Minimise sunlight on the dam by planting vegetation on the north and west sides of the dam. Do not plant trees on the dam embankment.
  • Restrict stock access to dam to prevent disturbance to banks and sediments, and to stop stock defecating and urinating in the water. Provide alternative drinking water via troughs.
  • Occasionally de-sludge the dam to remove accumulated nutrients.

If you have a plant growing on your dam and you are unsure what it is, take a sample to your local office of the Department of Primary Industries for identification.


Source: http://gippsland.com/

Published by: news@gippsland.com



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