(Poll Hereford, Hereford and Poll Shorthorn calves)

An inborn error in branched chain keto acid metabolism that results in a progressive neurological disease that culminates in death before 5 days of age. At birth, affected calves are clinically normal, but within 24 hours they develop progressive neurological dysfunction characterised by uncoordinated limb movements that prevent the calves from rising. Between 48 and 72 hours after birth the calves collapse and typically are often found in lateral recumbency with opisthotonos. Death intervenes within 5 days of birth.

There are no pathognomonic gross findings at necropsy. Widespread vacuolation of white matter tracts in the brain and spinal cord is a common histological manifestation of MSUD in Hereford and Shorthorn calves.

Diagnosis