Facial Eczema (FE). Farmer Information Notes. Introduction

FACIAL ECZEMA NOTES

By Dr Clive Dalton

Original 1991 information written by Dr Barry Smith and Dr Neale Towers, Ruakura Agricultural Research Station, Hamilton, New Zealand.

BACKGROUND TO BLOG ON FE (2009)

In 1991 MAF’s Information Services Division produced technical leaflets called AgLinks, and I was a contributor to those as well as a technical editor getting other qualified people to write them. There were four on Facial Eczema, but they were rather heavy going I thought, and saw the need for more basic material as one-pagers in big print, so farmers need only use the relevant bits. The idea was timely, as the whole AgLink database died around 1980 when MAF's new 'commercial' managers decided we had to charge for information.

FE didn’t die with the AgLinks, so I got the two Ruakura top scientists, Dr Barry Smith and Dr Neale Towers, to write these “FE Notes” which I edited, and we mailed them out to farm advisers, telling them to photocopy the appropriate bits and give them away. We also mailed them direct to farmers on request at no charge, and told farmers and advisers to contact Barry or Neale directly for expert advice.

Smith and Towers had spent their careers on FE research at Ruakura as members of the thriving "Mycotoxic Diseases Research Group". It was closed down by the SOE AgResearch, that took over agricultural research in New Zealand.

These FE Notes disappeared along with MAF's variours divisons, but by a stroke of good luck, Neale Towers still had a copy which I have put on this Blog.

Warning: Some things have changed since 1991 so you'll have to take account of these as I have not updated the words. The only thing I have changed is to replace "contact MAF" with "contact your veterinarian'". The chemicals and products mentioned may now be out of date, so check with your veterinarian what is current. Prices are clearly out of date. Approval of products is now under the Animal Medicines and Veterinary Medicines (ACVM) Act and must also be approved by New Zealand Food Safety. Ask your veterinarian for the latest information on approved products. It is against the law to use an animal remedy that does not have a license or an approval of some sort, and your vet will tell you what happens when you use drugs 'off label'.

In 1991 we didn't remind farmers that horses don't get FE and this question comes up from time to time. Also at that time Camelids (Llamas and Alpacas) were not common on farms and we now know that they can get FE, so check with your veterinarian about prevention measures for them and treatment of sick animals. Zinc boluses for sheep and beef cattle were not invented in 1991 and counting spores in faeces instead of pasture is a recent development.

The titles of the series is as follows.
1. Facial Eczema: Cause and symptoms.
2. Facial Eczema: Fungicides in FE control.
3. Facial Eczema: (Dairy Cattle). Management.
4. Facial Eczema: Zinc oxide. General dosing information.
5. Facial Eczema: (Dairy Cattle). Zinc oxide. Long-term dosing.
6. Facial Eczema: (Dairy Cattle). Zinc oxide. Crisis dosing.
7. Facial Eczema: (Dairy Cattle). Zinc oxide. Dosing with motor-driven systems.
8. Facial Eczema: Zinc oxide. Prevention by pasture spraying.
9. Facial Eczema: (Sheep): Zinc oxide. Long-term dosing.
10. Facial Eczema: (Dairy cattle). Zinc sulphate. In drinking water.
11. Facial Eczema: (Dairy cattle). Zinc sulphate. Using in-line dispenser.
12. Facial Eczema: (Dairy cattle). Zinc sulphate. Direct addition to supply tank.
13. Facial Eczema: (Dairy cattle). Zinc sulphate. Direct addition to trough.
14.Facial Eczema: (Dairy cattle). Zinc sulphate. Using in-trough dispensers.
15. Facial Eczema: (Sheep & beef cattle). Grazing management.
16. Facial Eczema: (Goats). Management.
17. Facial Eczema: (Deer). Management.
18. Facial Eczema: (Sheep). Mangement. Minimising losses after outbreaks.
19. Facial Eczema: (Sheep). Breeding. Buying FE resistant rams.
20. Facial Eczema: (Sheep). Breeding. Breeding resistant rams.

How to find each of the above items
Copy and paste the title from the list above - and enter it into the Google search box at the top left hand side of the blog front page.

Spring Eczema
This is a condition which veterinarians say is not Facial Eczema as it occurs in spring, when FE is an autumn disease. The cause of Spring Eczema is not know, but speculation is that 'it's something in the feed".  It certainly looks like classical FE and it pays to treat it as such.

 

Picture of animal with a healed eczema scab on white area of its back

Disclaimer

This material is provided in good faith for information purposes only, and the author does not accept any liability to any person for actions taken as a result of the information or advice (or the use of such information or advice) provided in these pages.

Facial Eczema (FE). Farmer Information. Part 1. Cause & symptoms.

Agriculture, animal husbandry, Facial Eczema, causes, symptoms, cattle, sheep, deer, goats

By Dr Clive Dalton

Original 1991 information written by Dr Barry Smith and Dr Neale Towers, Ruakura Agricultural Research Station, Hamilton, New Zealand.

Part 1. Cause and symptoms.
Facial eczema (FE) is a disease of sheep, cattle, deer and goats, which causes death and lowered production from liver injury. During periods of warm humid weather between January and April, the pasture fungus Pithomyces chartarum multiplies and produces spores which contain the toxin, sporidesmin.

Spores are easy to identify as they look like brown hand grenades.  

If they look black, they are old and less toxic.

Sporidesmin causes injury to the liver, the bile ducts become thickened and may be completely blocked. The damaged liver then cannot rid the body of wastes and a breakdown product of chlorophyll accumulates in the tissues and causes sensitivity to sunlight. Sunlight causes immediate and severe skin inflammation to exposed parts of the body.

 Damaged liver

FE can be so severe and stressing that it causes death. Animals can survive and recover from the disease, but the effects of the acute disease on growth, body weight, wool and milk production can be dramatic. Even if the liver damage is insufficient to cause photosensitisation, there can still be "sub-clinical" effects on the production of meat, wool and milk.

In any FE outbreak, many animals with liver damage show no clinical signs - but they suffer from sub-clinical FE. The appearance of the clinical condition results from spore consumption some 10-20 days earlier and the toxic spore level may have taken one to several weeks to develop.

Toxic conditions
For rapid growth and spore formation, the fungus needs warm, moist conditions and these are frequently supplied by the flows of tropical air from the north and east common during the autumn. Humidity is normally very high and 4-5 mm of rain or even heavy dews, in conjunction with 2-4 nights when grass minimum temperatures remain above 12-13°C, are sufficient to initiate rapid increases in spore numbers.

Spore counts rise even more rapidly when higher grass minimum temperatures (1 5-1 6°C) are associated with high humidities and/or light rain. Generally it takes two or three such "danger" periods before spore numbers reach dangerous levels, each spore rise providing the base for the next increase in spore numbers.

However, prolonged periods of warm, humid weather early in the season can accelerate the onset of toxic pastures. There is no such thing as an unqualified "dangerous spore level".

• The toxicity of a pasture at any one time depends on several factors: The spore count.
• The age of spores in the pasture (old spores are less toxic).
• The grazing intensity and level of the pasture being consumed. (Animals grazing down to the base of the pasture are at most risk.)
• Prior exposure of animals to toxic spores (makes them more susceptible).
• The susceptibility of different breeds and species.
• The length of time for which the high spore level is present and consumed.
  

Depending on the above factors, the level of spores on pasture may prove to be toxic anywhere above 40,000 spores/gram of grass (wash count), and long-term ingestion of low levels of spores may also lead to FE. Spore numbers can vary within and between paddocks depending on the topography, aspect, altitude and previous management practices.

Clinical signs
Species vary in their susceptibility to FE. Fallow deer and sheep are most susceptible, followed by dairy cattle, beef cattle and red deer, then most resistant are goats. Breeds vary within species, as do flocks and herds within breeds.

Sheep
The earliest signs of FE are increased restlessness, head shaking, scratching, rubbing of the head and shade-seeking behaviour. The exposed areas of the skin about the face and ears become swollen and thickened. The ears will droop. Later there is exuded serum and scab formation. This may be worsened by damage to the skin by the animals rubbing. Other areas affected are the vulva and the coronet above the hooves. Severely affected animals show jaundice.

Cattle
The first sign of FE in dairy cattle is a marked drop in milk production occurring soon after the intake of toxic spores and this occurs again after the onset of clinical FE. The animal will be restless at milking time, seek shade, and lick its udder. The clinical signs of FE are the thickening and peeling of exposed unpigmented or thin skin. Areas most affected are the white areas, the escutcheon and inside of hind legs, the udder and teats, and the coronets. The tip of the tongue is sometimes affected.

Deer
Deer appear to be more disturbed by the irritation of photosensitisation. Affected deer are more restless and irritable and actively seek shade. They frequently lick their muzzles and lips and the tongue tip becomes ulcerated. The lips and muzzle and areas about the eyes become affected and temporary blindness may develop. Deterioration rate and mortality appear to be higher in deer. Fallow deer are more susceptible than other species.

Goats
Goats develop crusty lesions about their eyes and lips and the ears may become thickened. Occasionally little more than a sunken weepy eyed appearance is seen. They will seek shade.

Disclaimer

This material is provided in good faith for information purposes only, and the author does not accept any liability to any person for actions taken as a result of the information or advice (or the use of such information or advice) provided in these pages.