Studies on the Relationships between Rumen Acids and Fat Metabolism of Ruminants Fed on Restricted Roughage Diets

The influence of ration preparation and level of concentrate upon rumen protozoa and volatile fatty acid production in sheep

“…According to Van Soest and Allen (1959)» the feeding of restricted amounts of roughage to dairy cows resulted in a depression in the fat content of milk but this was not accom panied by a lower acetate level. Propionate level was sig nificantly increased and appeared to be associated with a decrease in blood ketone bodies.…”

Absorption and metabolism of longchain fatty acids by bovine rumen mucosa

“…(1956) and by Van Soest and Allen (1959) as well as others, may account for the lower ketone production in rumen tissue, especially in the con trol animal. As was mentioned previously, the accidental feeding of the fasted animal 2 days prior to slaughter could very well have decreased the ketogenic activity of the papillary tissue somewhat in this animal.…”

“…In this way, deleteriously high concentrations of fatty acids are avoided, p-hydroxybutyrate is prob ably also very important in the lactating dairy cow, where its role as a precursor in milk fat synthesis in the mammary gland has been suggested by Van Soest and Allen (1959) and others.…”

Dietary factors affecting volatile fatty acid production in the rumen

“…Van Soest and Allen (1959) observed that high concentratelow roughage type diets narrowed the acetate-propionate ratios and produced significant declines in milk fat percentage. Balch and Rowland (1959) found that the administration of sodium acetate to cows in which the milk fat percentage had been reduced by diets low in hay and high in concentrates usually brought about an appreciable improvement in fat per centage.…”