In sheep, ketosis, evidenced by hyperketonemia with beta-hydroxybutyrate in blood over 0.7 mmol/L, occurs in pregnancy toxemia. This may develop in late pregnancy in ewes bearing multiple fetuses, and is associated with the considerable glucose demands of the conceptuses. In ruminants, because most glucose in the digestive tract is metabolized by rumen organisms, glucose must be supplied by gluconeogenesis, for which propionate (produced by rumen bacteria and absorbed across the rumen wall) is normally the principal substrate in sheep, with other gluconeogenic substrates increasing in importance when glucose demand is high or propionate is limited. Pregnancy toxemia is most likely to occur in late pregnancy because most fetal growth (and hence most glucose demand) occurs in the final weeks of gestation; it may be triggered by insufficient feed energy intake (anorexia due to weather conditions, stress or other causes), necessitating reliance on hydrolysis of stored triglyceride, with the glycerol moiety being used in gluconeogenesis and the fatty acid moieties being subject to oxidation, producing ketone bodies. Among ewes with pregnancy toxemia, beta-hydroxybutyrate in blood tends to be higher in those that die than in survivors. Prompt recovery may occur with natural parturition, Caesarean section or induced abortion. Prevention (through appropriate feeding and other management) is more effective than treatment of advanced stages of ovine ketosis.
The ketogenic diet is a medical nutrition therapy that involves participants from various disciplines. Team members include a registered paediatric dietitian who coordinates the diet programme; a paediatric neurologist who is experienced in offering the ketogenic diet; and a registered nurse who is familiar with childhood epilepsy. Additional help may come from a medical social worker who works with the family and a pharmacist who can advise on the carbohydrate content of medicines. Lastly, the parents and other caregivers must be educated in many aspects of the diet for it to be safely implemented.