Literally low blood calcium level, hypocalcaemia is rare because blood calcium is controlled by releasing calcium from bone under the control of parathyroid hormone to maintain homeostasis. Low serum calcium can cause muscle spasm in mares during peak lactation similar to the ‘’milk fever’’ seen in dairy cows and dogs where it is more common. It may also precipitate an episode of ‘’Thumps” or Synchronous Diaphragmatic Flutter, similar to hiccoughs when the diaphragm contracts in synchrony with the heartbeat, usually after prolonged exercise and heavy sweating with substantial loss of electrolytes including calcium.

Hypocalcaemia can be related to low dietary calcium intake or a calcium / phosphorous imbalance in the ration. See Hyperparathyroidism

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