Clinicopathological Phenotype of Autosomal Recessive Cholesterol Deficiency in Holstein Cattle

Mock, T.; Mehinagic, K.; Menzi, F.; Studer, E.; Oevermann, A.; Stoffel, M.H.; Drögemüller, C.; Meylan, M.; Regenscheit, N.

The main limitations for the diagnosis of CD in cattle are the unspecific clinical symptoms of diarrhea and failure to thrive in young calves. It is important, as demonstrated by the affected animals described here which belong to an age group most susceptible for various diarrhea-causing pathogens, to first exclude common agents causing diarrhea. However, as shown by the findings of 2 calves excreting oocysts of Eimeria bovis and Cryptosporidium parvum and, in the case of the heifer, Trichuris spp., CD can be present concomitantly with pathogens causing diarrhea. In case of intermittent diarrhea resistant to treatment in young Holstein cattle, analysis of total cholesterol and triglycerides can lead to a suspicion of CD. Pathological investigations are only diagnostic, if samples of the small intestine are immediately fixed in formalin (within minutes after euthanasia). Otherwise, the lipid vacuoles in the enterocytes of the villi tips are lost due to immediate autolytic changes in the small intestine. A clinical or pathological suspicion of CD should be confirmed using the gene test detecting the APOB mutation after consideration of pedigree information indicating inbreeding linked to the founder sire Maughlin Storm. 3 This newly developed diagnostic tool will allow a reduction in unnecessary treatment costs, use of antibiotics, and time-consuming care of affected animals. The early diagnosis of CD will enable targeted eradication of the APOB mutation from the Holstein population and thus prevent economical losses in the future.