A comparison of normal concentrations of reducing sugar, volatile fatty acids, and ketone bodies in the blood of lambs, pregnant ewes, and non-pregnant adult ewes

Abstract

Concentrations of reducing sugar, volatile fatty acids, and ketone bodies were estimated in blood drawn from six normal Merino ewes before and during pregnancy and on their lambs from birth until 4 months of age. During pregnancy the concentrations of glucose and volatile fatty acids remained within the pre-pregnant range. A significant rise in blood ketones (P < 0.001) occurred with some values as high as 8.8mM (35 mg/100 ml) during the last month of pregnancy, indicating that the normal ewe is predisposed to ketosis during the pre-partum period. In the lambs the blood glucose range was 79-115 mg/100 ml for the first 2 weeks. There was a gradual fall until adult values (39 ± 6.2 mg/100 ml) were assumed at 13 weeks. This fall commenced 2-4 weeks before rumination was observed and so it was probably not entirely due to the development of rumen function. The volatile fatty acids were always within the adult range, which indicated that lambs have a major source of volatile fatty acids other than the rumen. Ketone concentrations of (2.5 ± 1.14) mM found in lambs between 1 and 90 days old were higher than those of adults ((1.5 ± 0.84)mM). The katabolism of dietary milk f a t might be responsible for the high concentrations of circulating volatile fatty acids and ketone bodies.