Metabolic moments in ewes – Pregnancy toxaemia ‘vs’ Milk fever - Elders Rural Services

Metabolic moments in ewes – Pregnancy toxaemia ‘vs’ Milk fever

Managing the nutritional status of livestock over winter can present some challenges – dry feed becomes limited and for those approaching lambing, pregnant ewe’s nutritional requirements are increasing. If this is not managed carefully, ewes can go into a negative energy balance and are at a higher risk of metabolic conditions, such pregnancy toxaemia and milk fever. Understanding and recognising the signs of these conditions are crucial to correct management and treatment to minimise their impact on a flock’s health.

Pregnancy toxaemia (or Twin lamb disease) is caused by insufficient energy during late pregnancy. With low energy supplies fat reserves will be utilised as an energy source, which at high levels causes damage to the brain and nervous system. Older ewes and those carrying twins or triplets are most at risk, and it will usually affect them in the last two weeks of pregnancy. Bad weather, disease or yarding, which can reduce appetite, can also trigger this condition.


So what signs should you look out for? Often affected ewes will be separated from the mob, and appear depressed with tremors and an unusual posture. Ewes may appear blind, become recumbent and death can occur 3 to 4 days later. Veterinary advice can be sought to confirm a diagnosis and advice on the most appropriate treatment option. An oral energy supplement is commonly used, such as Ketol® which aims to elevate blood glucose levels and support removal of ketone bodies which accumulate in the body. Ketol® will restore general metabolic function by assisting fatty acid metabolism, whilst improving appetite. Offer good quality dry feed if ewes are able to eat also. Without early treatment the condition is usually fatal – but with early treatment, before nervous signs develop, up to 50% of affected ewes will survive. Prevention requires nutrient rich pasture and the use of appropriate mineral supplements. Limiting stress on ewes will also be important in managing ewes prior to lambing.


Milk fever (or hypocalcaemia) is also a condition affecting lambing ewes, but with a very different cause to pregnancy toxaemia. Milk fever results when ewes cannot mobilise calcium from their bones quickly enough to meet their demand. Blood calcium levels drop and muscles cannot contract properly. Milk fever can occur in late pregnancy, early lambing or affect other sheep in good condition, particularly if they are stressed from yarding or extreme weather. Sheep with sudden feed changes, especially onto green cereal crops which are low in calcium, or grazing on pasture with high oxalate content are also at risk.

So what happens when ewes get milk fever? Milk fever has rapid onset, and clinical signs include restlessness, muscular tremors, stiff gait and bloat. Ewes can become recumbent and death can occur within 24 hours, so rapid intervention is required. A common remedy is an injectable calcium solution, such as Flopak® Plus 4 in 1. This can be administered subcutaneously (or by intravenous injection if under veterinary supervision) to replenish tissue calcium levels quickly. Recovery, if treated earlyis usually rapid and will typically confirm the diagnosis. Prevention of milk fever is best achieved by ensuring ewes have been well supplemented with calcium during their pregnancy and then using well balanced prelambing mineral licks such StayDry Pre-Drop.

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For assistance with this issue in your flock, your local Elders Livestock Production Advisor may be able to help.

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