April 13, 2012

New Zealand Sheep - Facial Eczema damaged liver

By Dr Clive Dalton

The fungus Pithoymyces chartarum is found in pastures mainly in the Northern parts of New Zealand, and in autumn after a summer dry period when a lot of dead litter has accumulated in the pasture base, rain and dew can provide ideal conditions for the fungus to produce spores in large numbers. But the spores can also be found in large numbers on new short fresh autumn grass.

The fungal spores, especially the freshly-grown ones produce a toxin called sporidesmin, which causes thickening of the bile duct and may even cause its complete blockage.

Sheep gall bladder punctured to show bile and healthy
bile duct entering the liver tissue

A damaged liver cannot get rid of waste products, and a breakdown product of chlorophyll accumulates in the tissues causing jaundice and sensitivity to sunlight.

Sunlight very quickly causes swelling and severe inflammation on exposed white skin parts of the body.

There can be some repair of the liver, but it depends very much on the level of damage. In a recovered liver you will see knew small lobes that have grown.

Sheep's liver cut through centre

The liver pictured above is from a 6-year-old ¾ Romney ewe with ¼ Finn. She spent 5 years of her life on a farm that is very prone to FE, so there’s little doubt that she will have experienced a toxin challenge and liver damage during those years. She has reared twins most years in her life and it’s amazing that she was able to do this.

In the picture at the knife point is a little motley yellowish tissue on the surface of the liver which shows toxin damage. A real badly damaged liver is like a lump of wood.

But note especially the nice new healthy liver lobe on the right of the picture, and the 3 new small ones at the top right, and how healthy the internal tissue is.

For the last two seasons, this old ewe has been treated regularly with a zinc-based nutritional supplement which has protected her from further liver damage by toxins, and helped to stimulate new healthy liver growth.

Internal signs of a dysfunctional liver
Often at post mortem of a ewe dying close to lambing, you'll find two dead almost mummified lambs insider her but great masses of fat in the body cavity which the liver has not been able to process to nurture the lambs.

No comments:

Post a Comment