The pathology of the skeletal and cardiac muscles of cattle with xanthosis

Abstract

The pathology of xanthosis was studied in 5 adult Ayrshires and 4 Friesians from and abattoir in which 217 incidents occurred in 1 year and in which there was an incidence of 9 per cent in Ayrshires and <1 per cent in Friesians. Xanthosis was detected ante-mortem by examination of the coat colour. At post-mortem examination, there was grossly visible pigmentation in the heart, usually also in the Mm. masseter and diaphragma, sometimes in other skeletal muscles and in the sub-capsular zone of the adrenal cortex. The grossly visible pigmentation was considered to be due to the presence of an intracellular, and in muscle cells paranuclear, autofluorescent pigment. The tinctorial characteristics and ultrastructural morphology strongly suggest the pigment to be a lipofuscin. The most severe degree of pigmentation occurred in the oldest cows. There was no significant difference in the pathology between Ayrshires and Friesians. Three Ayrshires also had a myopathy which, at least in 2 animals, appeared to represent a stage in the process of lipofuscin formation. A tinctorially similar pigment was found locally in the kidney tubule cells, in the glia and perivascularly in the cerebral cortex and hippocampus of a single Ayrshire affected with xanthosis.