The pathology of post-parturient fatty liver in high-yielding dairy cows.

The pathology of post-parturient fatty liver has been studied in a group of 20 high-yielding dairy cows; 10 had less than 20 per cent fat in the liver cell and were classified as having a mild fatty liver and 10 had more than 30 per cent fat in the liver cell and were classified as having severe fatty liver. Severe fatty liver was accompanied by a number of morphological changes including the occurrence of lipogranulomas, increased liver cell volume, decreased volume of rough endoplasmic reticulum per liver cell and evidence of mitochondrial damage. The latter two changes were reflected in reduced albumin levels and increased activities of mitochondrial enzymes observed in the blood of cows with severe fatty liver. Reduced fertility may be one of the consequences of severe fatty liver in the dairy cow.