A Study of Starvation Ketosis in the Ruminant

Abstract

In a biochemical study of ketosis in cattle and sheep following starvation periods of 4-6 days starvation resulted in a rise in pH of rumenal contents associated with a fall in volatile fatty acids due to lowered bacterial activity. A non-pregnant cow or a dry-cow in the early stages of pregnancy is apparently able to withstand a period of semi-starvation without developing marked ketonemia. Glycogen reserves may be sufficient to maintain normal metabolism in such cases. At peak lactation, starvation causes marked ketonemia. In such cases considerable acetoacetate is probably formed from breakdown of body fat and rapidly excreted or converted to free acetone of beta-hydroxybutyric acid. These fractions may be passed via the blood stream to the milk, urine and to the rumen. In the rumen some conversion of acetone to isopropanol may take place and low levels of this latter constituent were detected in milk and urine. The ketonemia produced in ewes in late pregnancy was similar to that found in lactating and pregnant cattle. Concn. of ketone bodies in blood, milk, urine and rumen liquor is given.