Pregnancy toxaemia — also known as twin lamb disease or ketosis — is a metabolic disorder of late-pregnant ewes causing progressive neurological signs, recumbency, and death without treatment. It is a preventable condition representing significant welfare failure when it occurs.
In late pregnancy, ewes carrying multiple lambs have dramatically increased energy requirements. When energy intake fails to meet demands — particularly in the final 6 weeks of pregnancy — ewes mobilize body fat, producing ketone bodies that accumulate to toxic levels. Affected ewes show progressive welfare compromise: depression, blindness, muscle tremors, teeth grinding (a pain indicator), recumbency, coma, and death.
The progression from early signs to death can occur within 2-5 days without treatment. The condition causes intense suffering — affected ewes that survive describe-equivalent stress responses including cortisol elevation and pain behaviors.
Twin- and triplet-bearing ewes are most vulnerable. Risk factors include: inadequate energy feeding in late pregnancy, poor body condition at mating, sudden diet change, cold stress, transport stress, and competition at the feed barrier preventing adequate intake by submissive ewes.
Pregnancy toxaemia is almost entirely preventable with good nutritional management. Key prevention strategies include:
Early cases respond to oral propylene glycol (250ml twice daily) providing immediate glucose precursors. Advanced cases require veterinary treatment including intravenous dextrose, corticosteroids to induce parturition in near-term ewes, and supportive care. Prompt intervention prevents progression from early neurological signs to irreversible coma.
Pain management with NSAIDs is a welfare priority alongside metabolic treatment — affected ewes show clear pain indicators and benefit from analgesia.
Prevention requires proactive monitoring — daily observation of late-pregnant ewes with attention to bright, alert demeanor and normal feeding behavior. A ewe found standing away from the flock, dull, or not eating in late pregnancy should trigger immediate assessment. Early identification and treatment significantly improves welfare outcomes and recovery rates.