Species: Cattle and sheep

Specimens: Serum or eye fluid (in recently dead cows or sheep)

Optimum number of animals to test for mob/herd/flock: 8-10

General information about the test:

Magnesium is a stable element.  Magnesium deficiency occurs most frequently in dairy and beef cattle in the late winter and spring period. This deficiency can be due to a combination of low magnesium and high potassium in spring pasture, the application of slurry to pasture and nutritional stress.  A variety of clinical signs may be observed in a deficient herd from peracute (found dead) to chronic (unthrifty cows with  and udder oedema).   An increased incidence of milk fever and reduced milk yield can indicate subclinical hypomagnesaemia in a herd.  Wet cold days and the pasture is wet and lush may precipitate attacks as cows will have lower intakes of pasture.  Clinical hypomagnesaemia also occurs in sheep – the causes are similar to those seen in cattle.

Reference Interval:

  • Cattle – Supplied with results
  • Sheep – Adequate  0.74 -1.15 mmol/L
  • Eye fluid – Adequate  > 0.6 mmol/L