Effect of Facial Eczema on Production

Whatawhata trials (Sheath and Webby APS 1987), Rex Webby and Neale Towers

Each 100 unit increase in GGT meant a:

Flock mean GGT in range 150 to 250 this meant 12% more cull or dry ewes and 14% less ewes lambing multiples.

Also an effect on lamb weaning weight is observed. For example:

Approximate relationships between GGT and lamb production

GGTExpected drop in lambing %Drop in wool productionDrop in weaning wtlost income per ewe@ 100% lambing
1002.4 to 11.40.6%0.6kg$3.30
2004 to 151.5 %1.4kg$4.30
30012 to 182.6 %2.6kg$8.98
40014 to 302.6 %2.6kg$11.33

The effect on wool production and lamb weaning weights becomes confounded, as GGT increases, by the fact that there are fewer multiples and more dry ewes.

Interpretations of categories of damage based on GGT level vary but these may help:


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