Symptoms of lambing sickness and milk fever in heavily pregnant ewes are often very similar.
You can identify early signs of the diseases during mustering or yarding for the pre-lambing shearing or crutching. Signs include drooping of the head, lagging behind the rest of the flock and walking aimlessly.
You'll need to examine ewes displaying these signs and consider their recent history to work out the right diagnosis. Then you should start treatment as soon as possible while it can still be effective.
Identifying the typical symptoms of lambing sickness and milk fever
| Lambing sickness|| Milk fever|
Slow progression of the disease with death after 5-7 days.
Rapid progression of the disease with death after 6-24 hours.
Early and late signs
- separation from the flock
- apparent blindness with alert bearing but disinclination to move
- standing still when approached
- blundering into objects when forced to move and pressing their head's into obstacles
- may stand in water all day lapping water.
In the later stages:
- marked drowsiness
- tremors and spasms of the head, face and neck muscles with the head pulled back or sideways
- abnormal postures, elevation of the chin ('star-gazing'), muscle tremors on legs, incoordination, falling and convulsions
- there may be a thick, often yellowish and candlewax-like discharge from the nose.
- stilted proppy gait
- muscle tremor, especially in the shoulder muscles
- alertness and struggling when approached
- weak appearance, staggering about and going down. Once ewes go down, they tend to stay down unless effective treatment is given.
Recumbency (lying down)
- slow progression to recumbency 2-3 days after onset of initial signs
- profound depression or coma until death 2-6 days after onset of signs.
- rapid progression to recumbency over 3-4 hours
- sternal recumbency with the head stretched out and chin on the ground with legs folded beneath or stretched out behind the ewe is usual
- watery discharge from nose may occur
- vaginal prolapse may occur.
- drowsy appearance rapidly gives way to severe depression and coma
- death is usually rapid, within 6-24 hours without treatment. Some cases may linger for up to 3 days.
Response to treatment
- no response to hypocalcaemia treatment dose rates of commercial calcium solutions
- varied (but usually poor and slow) response to doses of glucose or energy, with best responses seen if treated whilst ewes are still alert.
- rapid and good recovery after injection of treatment doses of commercial calcium solutions, even in the later stages
- signs of recovery seen from within a few minutes to about half an hour of the injection.
- liver is yellowish with a fine mottled appearance characteristic of pregnancy toxaemia
- abdominal fat shows white flaky or chalky patches indicative of fat breakdown.
- there are usually no significant and characteristic observable post-mortem findings.
Diagnosing and separating sick ewes
Milk fever can also be involved in the death of a ewe that you see displaying rapid signs of lambing sickness.
If you run more intensive sheep-raising conditions, it's a lot easier to tell the diseases apart. You'll be able to observe the sheep more often and over longer periods of time, letting you differentiate between the early signs more easily.
If you see any of the early signs during mustering, don't force affected ewes to continue. Retrieve them in a vehicle, hold them in the yards or a small holding paddock and follow the appropriate treatment.