Camelidae and Cervidae Hepatic Lipidosis – NAVLE Study Guide

Overview and Clinical Importance

Hepatic lipidosis (HL), also known as fatty liver disease, is a critical metabolic disorder characterized by excessive accumulation of triglycerides within hepatocytes. In camelids (llamas and alpacas), HL is arguably the most common liver disease encountered and carries a guarded to poor prognosis if not recognized early. Unlike dairy cattle where HL is primarily periparturient, camelids can develop HL across all ages, genders, body conditions, and reproductive states.

In cervids (deer, elk), hepatic lipidosis presents differently. During the rutting season, male cervids naturally develop a physiological fatty liver that is subclinical and reversible. However, captive cervids under stress or with inadequate nutrition can develop pathological HL similar to other ruminants.

Pathophysiology

Normal Lipid Metabolism

Under normal conditions, the liver plays a central role in lipid metabolism. During negative energy balance (NEB), adipose tissue is mobilized, releasing non-esterified fatty acids (NEFAs) into the bloodstream. These NEFAs undergo: (1) beta-oxidation for energy, (2) re-esterification into triglycerides and export as VLDLs, or (3) conversion to ketone bodies. Hepatic lipidosis develops when NEFA uptake exceeds the liver's capacity for oxidation and export.