Development and evaluation of an enzyme immunoassay for sporidesmin in pasture

Abstract

An enzyme immunoassay was developed which could detect sporidesmin in pasture samples. The assay had a linear working range of 0.4-40 ng/ml sporidesmin A while validation using pasture extracts gave mean percentage recoveries of 124% for samples containing 1 ng/ml sporidesmin and 97% for extracts containing 20 ng/ml sporidesmin. The sporidesmin levels and numbers of Pithomyces chartarum spores from many pasture samples were compared. The amount of sporidesmin detected generally corresponded to the number of spores found in the sample.

Effects of low dose rates of sporidesmin given orally to sheep

“…The clinical disease has been reported to cause considerable stress as measured by serum cortisol changes (Smith and Payne, 1991). It has been reported that Pithomyces spores contain approximately 70 ng of sporidesmin-A per 100,000 spores (Collin et al, 1995). In another study, that used the azideiodine reaction, it was reported that the average sporidesmin content of pasture-collected spores was 98 ng sporidesmin-A per 100,000 spores (Clare and Gumbley, 1962).…”

“…The increased weight of hepatic lymph nodes and the oedema present has not been previously reported. It is suggested that this arises from injury to and drainage from (May, 1955) the extra-and intrahepatic biliary system. Skin weights, especially but not exclusively from those of animals suffering from photosensitisation, were decreased.…”

Effect of feeding metal amino acid complexed trace minerals to dairy cattle for the prevention of facial eczema

“…Low pasture covers also required supplementary feeding of cows with grass and corn silage beginning midJanuary (week 25). P. chartarum spores counts greater than 100,000 per gram of pasture are considered to place animals at risk of facial eczema when pasture is essentially the sole source of dry matter intake (Collin et al, 1995). With the exception of week 33, P. chartarum spore counts were equal to or greater than 100,000 per gram of pasture during weeks 31-39.…”

“…The sporidesmin dose used by Smith (2000) was similar to the calculated range of sporidesmin-A doses (0.004-0.013 mg/kg BW) observed in the present study. This is based on spores containing approximately 70 ng of sporidesmin-A per 100,000 spores (Collin et al, 1995), an average cow weight of 475 kg BW, an estimated pasture intake of 15 kg, and spore counts ranging from 150,000 to 600,000/g of pasture (Fig. 1).…”