Pithomycotoxicosis, more commonly known as facial eczema (FE), is a liver disease that occurs predominantly in New Zealand because of its toxigenic Pithomyces chartarum strains. The first reported case was in sheep in 1887. Since the 1930s, a number of studies have been conducted in an attempt to mitigate the problems FE has on the sheep and dairy industries. The research in these studies included work on fungicide and biological control of the saprophytic fungus, use of different pasture plants to inhibit fungal growth, stock management with respect to pasture fungal spore counts and the use of zinc prophylaxis on animals. The finding that there was a genetic basis in FE sensitivity in sheep prompted research for a genetic approach to mitigation in the form of a diagnostic DNA test for susceptibility to the disease. Recently, we have used the Illumina OvineSNP50 BeadChip to develop a genome-enabled prediction approach to screen for FE-tolerant sheep. Our current best genomic prediction for FE is for the Romney breed and has an accuracy of 0.38. This prediction accuracy is not as high as the individual accuracy gained by an artificial challenge test (0.64). However, it has the advantage of being a non-invasive test and can be provided as part of genomic testing for other traits at minimal cost.
Keywords: 50K-SNP array; liver mycotoxicosis; multifactorial disease; ruminants; whole-genome selection; xenobiotics.
© 2014 Stichting International Foundation for Animal Genetics.