Lambing disease is well recognized, but what about milk fever?

Milk fever in sheep

Milk fever in sheep can occur any time from 6 weeks before, through to 10 weeks after lambing. It most commonly occurs in the last 1-3 weeks of sheep gestation. Calcium demand during this period is high. When there is an abrupt decrease in feed intake, the body needs about 48-72 hours to mobilise calcium from the bones. This will result in a decrease in blood calcium levels.
Milk fever can occur concurrently with ketosis in sheep.

Clinical signs of milk fever  in sheep

Characteristically, milk fever in sheep occurs in outbreaks, involving multiple animals, although it is not uncommon for individual sheep to be affected. Usually, less than 5% of ewes are affected, but severe outbreaks may involve up to 30% of the flock.

Clinical signs are very similar to sheep ketosis, but progression is usually much faster. Signs include drowsy appearance, depression and coma, salivation, a stiff or staggering gate, sternal recumbency with the head stretched out and the chin on the ground with legs folded beneath or stretched out behind the ewe.

How to maintain blood calcium at the correct level?

Ensure the diet during the last few weeks of sheep gestation and the first few weeks after lambing contains sufficient calcium. Examples of feed with low calcium levels include grains, straw, poor quality hay and pasture and corn silage.
Vitamin D deficiency, which occurs in housed sheep during winter months, also depresses calcium absorption from the gut. Ensure there is enough trough space and avoid sudden changes of the ration; extra feed will be required in bad weather. Consider providing a supplement containing energy and calcium immediately after lambing.

Sheep with milk fever

Once the animal is depressed it will not eat anymore; contact your vet who can give the animal an i.v. infusion. A good and lasting response to such an infusion confirms the diagnosis of milk fever was correct.

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