Neuroaxonal dystrophy in Merino‐Border Leicester × Polled Dorset lambs

Abstract

This is the first report of NAD in such crossbred lambs; the affected animals were much younger than in previously described cases of ovine NAD and myelin loss was of much greater magnitude than previously reported.

Axonal Spheroid Accumulation In the Brainstem and Spinal Cord of A Young Angus Cow with Ataxia

“…7 In primary NAD, axonal spheroids are the principal pathological feature and their neuroanatomical distribution is concordant with the neurological deficit. 3 The topographical distribution of spheroids in the present bovine case closely resembled that found in ovine NAD, [8][9][10][11][12] with, however, some minor differences in neuroanatomical distribution. 1,3 The present case accords with this category and is, we believe, the first reported case of primary NAD in cattle.…”

“…3 The topographical distribution of spheroids in the present bovine case closely resembled that found in ovine NAD, [8][9][10][11][12] with, however, some minor differences in neuroanatomical distribution. 8,12 In terms of differential diagnoses, multifocal axonal spheroids in the brain accompany some lysosomal storage diseases and may contribute to the clinical presentation. 1,2,4 Hyperglycaemia is often observed in cattle with neurological signs and in moribund cattle, presumably mediated by catecholamine release.…”

“…Secondary NAD is expressed as a reactive process to another neurological or non-neurological disease, manifesting as either a marked accentuation of physiological NAD or widely distributed axonal spheroids in the brain contributing to the disease symptomatology. 3 The topographical distribution of spheroids in the present bovine case closely resembled that found in ovine NAD, [8][9][10][11][12] with, however, some minor differences in neuroanatomical distribution. This regional predilection favours involvement of afferent proprioceptive pathways and the predominant clinical presentation of progressive ataxia.…”

“…1,3 The present case accords with this category and is, we believe, the first reported case of primary NAD in cattle. 13 In the present case, as in previously reported ovine NAD cases, [8][9][10][11][12] axonal spheroids in the routine H&E sections varied greatly in size, staining intensity and morphology, suggesting they were at different stages of temporal evolution and/or of different aggregated protein composition. 3 The topographical distribution of spheroids in the present bovine case closely resembled that found in ovine NAD, [8][9][10][11][12] with, however, some minor differences in neuroanatomical distribution.…”

“…1,2,4 Hyperglycaemia is often observed in cattle with neurological signs and in moribund cattle, presumably mediated by catecholamine release. 13 In the present case, as in previously reported ovine NAD cases, [8][9][10][11][12] axonal spheroids in the routine H&E sections varied greatly in size, staining intensity and morphology, suggesting they were at different stages of temporal evolution and/or of different aggregated protein composition. Similar to axonal spheroids previously reported in ovine NAD cases, 8 those in the present case were often immunopositive to APP, although a few were immunonegative.…”