Maple syrup urine disease

From Cow

Maple syrup urine disease (MSUD) is a genetic disease of Hereford and polled Shorthorn breeds[1].

Affected calves are born with ataxia and characteristically sweet-smelling urine. As the disease progresses, calves become progressively worse, with neurological deficits resulting in an inability to walk, followed by recumbency and death.

Diagnosis is based on presenting clinical signs typical of encephalopathy[2] and laboratory tests on hair roots[3] using PCR assays[4].

A differential diagnosis would include other storage diseases such as citrullinemia, gangliosidosis and mannosidosis.

Because of the hereditary nature of this disease, affected calves are usually culled, or removed from any breeding programs.


  1. Healy PJ et al (2002) Genotyping cattle for inherited congenital myoclonus and maple syrup urine disease. Aust Vet J 80(11):695-697
  2. Dodd PR et al (1992) Glutamate and gamma-aminobutyric acid neurotransmitter systems in the acute phase of maple syrup urine disease and citrullinemia encephalopathies in newborn calves. J Neurochem 59(2):582-590
  3. Healy PJ & Dennis JA (1995) Heterozygote detection for maple syrup urine disease in cattle. Aust Vet J 72(9):346-348
  4. Dennis JA & Healy PJ (1999) Definition of the mutation responsible for maple syrup urine disease in Poll Shorthorns and genotyping Poll Shorthorns and Poll Herefords for maple syrup urine disease alleles. Res Vet Sci 67(1):1-6