OVINE pregnancy toxaemia - also known as twin lamb disease - is a major cause of mortality and ill-thrift at lambing time.

In this article, the National Disease Information Service (NADIS) gives a quick bullet guide to the disease and how to cope with it.

OVINE PREGNANCY TOXAEMIA IS MOST COMMONLY ASSOCIATED WITH:

- Multiparous ewes

- Three or more lambs

- During the last month of gestation

- Several weeks' energy underfeeding

ECONOMIC IMPACT:

- Response to treatment is poor, with mortality rates around 70%

- Many ewes have a fatty liver adversely affecting treatment outcome

CLINICAL SIGNS:

- Disorientation

- Isolation from the remainder of the flock

- Dull and depressed and are easily caught because they are blind

- Head pressing into the corner of a pen/fence

- Continuous fine muscle tremors around the muzzle and affecting the ears

- Ewe becomes recumbent with the hind legs held out behind

DIFFERENTIAL DIAGNOSIS:

The important differential diagnoses are

- Hypocalcaemia

- Listeriosis

- Impending abortion

- Cerebrocortical necrosis (CCN)

DIAGNOSIS:

- Diagnosis is based upon clinical signs

- Diagnosis confirmed on blood samples

TREATMENT:

- Response to treatment is generally poor

- Ewes should be penned separately and offered palatable feeds to promote appetite

- Oral propylene glycol or concentrated oral rehydration solution

- Glucocorticoid injection

PREVENTION:

- Scan ewes and feed appropriate ration based on foetal number

- Monitor body condition scores throughout pregnancy

- Check energy supply by measuring BHB in blood samples six weeks before lambing

- Ensure sufficient trough space and at ring feeders

- Weigh feed accurately, especially when using a snacker