Studies on the carbohydrate metabolism of sheep. VI. Interrelationships between changes in the distribution and levels of volatile fatty acid in the blood of lambs.

The post-absorptive blood glucose in lambs fell steadily with advancing age from levels of 85-90 mg. per cent. in the first week of life. Stable adult levels were reached in each of six lambs at an age of 6-9 weeks. A large proportion of the decline in whole-blood glucose was due to a steady and almost complete disappearance of glucose from the corpuscles; plasma-glucose levels tended to be maintained during the first 4-5 weeks of life. Corpuscle : plasma glucose ratios decreased from an initial range of 0.45-0.99 to less than 0.15. In eight adult sheep the ratios were in the range 0.0-0.26. Blood volatile fatty acid levels in fed lambs increased steadily with advancing age. Levels characteristic of adult sheep on the same rations were not reached until an age of at least three months. It is concluded that the fall in post-absorptive blood glucose in lambs and calves, with increasing age, is largely due to factors other than the functional development of the lumen and these are discussed.