Milk fever (hypocalcaemia)

Conditions when likely to occur:

Previous history on property.

Usually older cows (>5 years old).

Usually late pregnancy (also after calving in dairy cows).

Usually high producing and dairy cross cows.

Previous history of cow with hypocalcaemia.

Alkaline diets (high Na+, K+ and low SO4 = C1-).

Low calcium intake after calving (and high intake before).

Low roughage intake.

Fat cows > FS3.5

Clinical signs: inability to rise, dry muzzle, either just about to calve or recently calved.

Management strategy to prevent disease:

Avoid over-fat cows: FS<3.5

Ensure constant access to feed during calving and avoid grazing high-risk pastures (as for grass tetany).

Feed hay after calving (consider cost benefit) avoid hay before calving. Keep calcium intake less than 50g/day before calving.

Prevent hypomagnesemia.

Lower herd age structure as older cows are higher risk.

Respond to treatment with calcium borogluconate with a dose of 8–14g of calcium.