Sleepy Sickness

What is it?

Sleepy sickness (also known as ‘twin lamb disease’ or ‘pregnancy toxaemia’) is a metabolic disorder of sheep seen in late pregnancy and is caused by a mismatch in the energy requirements of the ewe and the energy provided (via feed). This mismatch can be due to low levels of nutrition being offered to pregnant ewes (especially in the last six weeks of pregnancy) but can also occur in multiple-bearing ewes, even when they’re offered adequate feed levels. 

Ewes carrying twins or triplets require 200-250% more energy than those carrying singletons and to add insult to injury the massively enlarged uterus takes up valuable space in the ewes’ abdomen meaning there is less room for the stomach to fill i.e. they physically cannot eat as much. 

The foetus’ require glucose (energy) for growth, and they will take all the energy they need from the ewe with complete disregard for the ewes' own requirements. Ewes compensate for low energy levels by utilising their fat stores. Fat is broken down into ketones, which can then be used by the body as an alternative source of energy. While useful in smaller amounts, ketones are toxic in high levels.  

As ketone levels rise, we start to see the following signs of toxicity:  

• Anorexia  

• Weakness   

• Teeth grinding  

• Neurologic signs (depressed, incoordination, impaired vision, head pressing, muscle tremors, subtle convulsions, lip twitching, and star gazing) 

• ‘Wool pull’ (where the wool plucks easily from the live animal)  

• Constipation 

• In the advanced stages; recumbency (down ewe) and death  

Treatment

Early and aggressive treatment is required if there is to be any chance of success. If you have a ewe in late pregnancy showing any of the above clinical signs, then please contact your large animal vet urgently to discuss the treatments required, the earlier she receives these the better, and arrange a vet visit for the first treatment if indicated (e.g. if she’s down).  

The following treatments are required:  

• An oral energy supplement (such as ‘Ketol’ or ‘Keto-Aid’). Give 60mls orally twice daily until appetite returns, for a maximum of 10 consecutive days.  

• An injectable form of calcium, magnesium, and energy (e.g. ‘Glucalphos’). Initially 100ml should be given intravenously by a vet, then 100ml under the skin every 6 to 8 hours  

• Anti-inflammatory medication every 48-hours  

• Always, always, always ensure free access to water and high energy feed!  

• Good nursing care is crucial for a positive outcome. These ewes require: 

  • Shelter from the elements (ideally in a hut) 

  • Clean, deep bedding such as straw for warmth

  • If she’s down, then regular turning from side-to-side reduces the likelihood of pressure sores occurring 

• Caesarean section may also be indicated in some severe cases.  

Many of these treatments can be had on hand and administered by you, however, if your ewe becomes recumbent (this can occur within a day!), or if she is not responding to treatment after a couple of days, prognosis is poor despite best efforts at treatment. Early veterinary intervention for down ewes and administration of intra-venous energy supplements gives the best chance of survival; however, recovery only occurs in about 30% of these more severe or advanced cases.