The effect of the increased dietary volatile fatty acids on the morphological and physiological development of lambs with particular reference to the rumen

Abstract

Acetic acid, propionic acid, and butyric acid were fed to lambs at a level of 4% of ration over the period of 3-8 weeks of age. The effects of this on weight gains and rumen development were measured.Separate pathways are involved in the metabolism of C3and C4V.F.A. in the rumen wall, and the enzyme systems involved can adapt to high levels of each acid in the diet. The adaptation is longstanding.The groups of lambs supplemented with propionic acid showed greater weight gains than the other groups.Propionic acid in some way increases the efficiency of V.F.A. utilization by the animal, possibly by reducing the heat increment, and/or reducing loss of energy as ketone bodies in the urine.At 9-12 weeks a higher efficiency of food utilization in the acetic acid group was observed.The stimulatory effect of acetic and propionic acids on papilla numbers was observed at 8 weeks.Some observations were made on histological sections of rumen papilla at 8, 12 and 16 weeks and their relationship to the diet.