Hypocalcaemia is low blood calcium. Calcium is essential for many body functions especially muscle contraction, nerve conductivity and bone strength. Maintenance of normal blood concentrations is achieved by a combination of release from bone stores and absorption of dietary calcium from the gut.
Animals are at risk of hypocalcaemia when:
The first three situations might occur in assembly points, the fourth at destination.
Early signs include excitement and muscle tremors. Staggering gait, recumbency, paralysis, coma and death follow. There is no fever.
Diagnosis is based on clinical signs, presence of risk factors and response to treatment. Fragility of bones and sometimes healing rib fractures may be present in sheep with prolonged dietary deficiency. Blood samples will have low calcium concentrations.
Before kidding/lambing, pregnancy toxaemia is the main differential diagnosis. Some animals have both diseases. In pregnancy toxaemia, the onset is gradual over a few days and response to calcium is slight and temporary.
Laboratory confirmation requires 2 mL of serum submitted chilled for calcium and magnesium estimation. In dead animals, submit aqueous humor for calcium estimation taking care to minimise cellular contamination from the iris.
Administer injectable calcium and magnesium solutions under the skin over the ribs. Massage well to speed absorption. Commercial solutions of calcium borogluconate are commonly used and should be warmed to body temperature before injection. A response is expected in a few minutes (burping, muscle tremors, voluntary movements) with full recovery usually within an hour. Treatment occasionally needs to be repeated. It is fatal if left untreated. Careful intravenous administration of calcium solutions may be considered for severe cases.
Avoid selecting old, over-fat, pregnant ewes and does for live export. Avoid interruptions to food and water availability. Feed roughage as hay, chaff or pellets high in fibre (to increase dietary intake and gut absorption of calcium) in high risk animals or conditions.