Ovine Pregnancy Toxaemia

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Ovine pregnancy toxaemia or “twin lamb disease” (TLD) is a common issue in ewes usually seen in the month before lambing. Therapy, once signs are seen, is often unrewarding and so appreciating the causes is important to ensure preventative strategies are put in place to help reduce losses.

Understanding the energy requirements and demands of the ewe around this time is key. The lamb is growing rapidly at this stage, 75% of growth takes place in the late stage of pregnancy and so anything that reduces available energy or increases demand can trigger the disease.

Factors that can influence available energy are closely linked to diet. Poor quality roughage or insufficient concentrates will clearly lead to a lack of energy. But also, sudden extreme weather or any problems that reduce the ewe feeding during this period can lead to problems.

Demand for energy is obviously greater in ewes carrying multiple lambs, hence the name, and also the live weight of those lambs.  This is why TLD is most likely to occur in lowland flocks where the older ewes with triplets (or more) are worst affected.

It’s important to note that handling around this time can affect both energy demand and availability. Moving flocks to housing, vaccination and other routine management tasks can increase energy demands at the same time as stress and disturbance can reduce feeding. Such practices should be done with care and only when absolutely necessary.

Diets should be well planned throughout pregnancy so that sheep enter the last few weeks in an optimal body score ready to face the increase demand as lambing approaches. Batch feeding of concentrates, for example based on body score and scanning information, will help target those ewes in most need and avoid waste. High quality roughage, if available, should be made available to ewes carrying multiples.

Ewes should be carefully watched for any early signs of TLD. Therapy can be unrewarding, but the earlier the disease is spotted, and therapy started the better. Behavioural changes can be the first signs, with the ewe becoming dull, seeking isolation or reluctant to come to a feeding trough. These can quickly progress to more definitive signs such as head pressing, head tremors and blindness. If left untreated collapse and death will be the result.

Therapy is focused on increasing the energy supply. This can involve specific products providing energy together with trying to get the ewe to feed as much as possible.

Propylene Glycol as a drench is a common first choice and easily administered when the problem is suspected. Glucose can also be given by slow intravenous injection, but this requires more skill and experience and best done with veterinary advice.

The ewe should be encouraged to eat, for example with easy undisturbed access to palatable food and fresh water, or high-quality grazing if available.

Affected ewes can often abort or start to lamb if close to term. This is a natural defence to reduce energy demands. Close and regular checking is therefore required as foetuses or lambs can typically fail to be expelled leading to severe toxic problems.

Response to therapy can be disappointing and even if surviving, ewes will often need to be culled. This emphasises the need to focus on prevention to avoid these potentially significant losses.

Multi Lamb Rapid from Nettex is a fast working, energy complex for ewes carrying multiple lambs. A 45ml feed will provide a ewe with additional energy that she needs quickly. This may be particularly beneficial for exhausted ewes in supporting their energy needs at this crucial time.