- In late pregnancy and early lactation, ewes and cows are under great metabolic stress.
- Their foetuses grow fast in late pregnancy, and after giving birth they have to produce a lot of milk.
- If their feeding is interrupted, eg by bad weather or by yarding, they can easily be tipped into fatal metabolic imbalance.
The result may be:
- Hypomagnesaemia (also called grass staggers in cows)
- Acetonaemia (also called sleepy sickness or pregnancy toxaemia or twin lamb disease in ewes and ketosis in cows),
- Hypocalcaemia (also called milk fever in cows).
- In all these diseases the first signs are usually a change of behaviour.
- This can be dullness, progressing to the stage where the animals go down unable to rise, or agitation with trembling and nervousness leading to convulsions.
- It is wise to discuss treatment options with a veterinarian before cases develop.
- It is very important to call a veterinarian at the first sign of trouble.
- Emergency treatment is vital if the animal is to survive.
- Many cows have residual liver damage caused by facial eczema in autumn and this could predispose them to metabolic disease.
- Other predisposing factors include poor body condition, a check in feed supply, cold wet windy weather and the stress of yarding or transportation.
- To prevent metabolic diseases, farmers should try to keep their feed supply steady or increasing, provide sheltered paddocks in bad weather and minimise the time stock spend in yards.