Journal of the Graduate School of Biosphere Science, Hiroshima University Volume 55
2016-12-25 発行

Chronic hypomagnesaemia on bovine ketosis

Yoshida, Shigeru
Cows in the dairy farm of Hiroshima University were affected by abnormal milk secretion named “the Utrecht abnormality of milk”, and these cows were suffering from osteoporosis. Calcium was released from bone to milk by the increased serum calcium level. The increased serum calcium was caused by the decreased serum magnesium level by a low magnesium intake from roughage less than 0.2% in dry matter. These cows were suffering from chronic hypomagnesaemia. Mass outbreak of bovine ketosis was occurred in this dairy farm. The levels of the blood serum Ca, Mg and inorganic phosphate (Pi) were 3.93 mEq, 1.84 mEq, and 4.95 mg/dl, respectively, in the average of milking 20 cows. These cows showed a low level of serum magnesium for many years. The 72 cows suffering from ketosis were also showed low serum magnesium level (1.77 mEq), a low serum calcium level (3.91 mEq) and low serum Pi level 5.06 mg/dl), compared with normal 93 cows (Ca 4.28 mEq, Mg 2.00 mEq, and Pi 7.81 mg/dl). They also showed low serum magnesium level as well as the cows of University dairy farm.
In the relationship between ketosis and chronic hypomagnesaemia, ketosis was caused by the metabolic disturbance from α-ketoglutarate to succinyl-CoA, i.e., oxidative decarboxylation in TCA cycle. This reaction needs TDP, Lipoate, CoA, NAD, FAD, and Mg as cofactors. This disturbance must be act the accumulation of acetoacetate and ketone bodies, such as acetoacetate, acetone and β-OHbutyrate. The injection of magnesium, such as MgSO4 and MgCl2, have an effect on bovine ketosis. New hypothesis can be proposed that ketosis and downer cow, suffering from chronic hypomagnesaemia, must be come down with beriberi of human, because beriberi is a one of metabolic disturbance of oxidative decarboxylation reaction.
Oxidative decarboxylation reaction
Low serum magnesium
Chronic hypomagnesaemia
The Utrecht abnormality of milk