Congenital hepatic fibrosis and cystic bile duct formation in Swiss Freiberger horses.

This study explores the finding of congenital hepatic fibrosis – a likely recessively inherited condition – in Swiss Freiberger breed horses, traced back to a single stallion.

Introduction

The research focuses on the study of congenital hepatic fibrosis in horses, a condition that has rarely been reported in horses previously. The condition is commonly observed in humans, cats, piglets, and dogs and is usually associated with either a recessive or dominant genetic inheritance. The incidence of congenital hepatic fibrosis is traced in the study to the Swiss Freiberger equine breed.

Study Method and Subjects

• The researchers adopted a retrospective approach, examining records from the Institute for Animal Pathology, University of Berne.
• They specifically looked into records of 30 foals that had liver lesions compatible with the characteristics of congenital hepatic fibrosis.

Findings from Anamnestic Data

• Most of the foals, all belonging to the Swiss Freiberger breed, showed clinical signs of severe liver injury.
• The livers of these foals were found to be severely enlarged, displaying firmness and having thin-walled cysts.
• Pathological examination showed that the liver tissue had diffuse porto-portal bridging fibrosis.
• The bile ducts in these livers were small, irregular in formation, and in some cases, cystic.

Genetic Inference

• The study also undertook a pedigree analysis, which revealed that the diseased animals could all be traced back to one specific stallion.
• This crucial piece of evidence suggests the possibility that the condition is not random but is likely an inherited autosomal genetic defect.
• Furthermore, the pattern of inheritance, given that it was traced back to one stallion, strongly indicates that congenital hepatic fibrosis in Swiss Freiberger horses may be a condition of recessive inheritance.