Effect of Silage Extract on Voluntary Intake, Rumen Fluid Constituents, and Rumen Motility

The effects of intraruminal infusion of juice expressed from second cutting untreated (Silage) and formaldehyde-formic acid treated (Formal) alfalfa silage were investigated in two fistulated wethers. Infusion of 2.25 liters Silage juice coincident with the morning feeding depressed voluntary intake of hay for 1.5 to 9 h and caused distortion in rumen motility. Formal juice had intermediate effects and water no effect. With infusions of Silage juice, maximum ruminal fluid volatile fatty acids (982 mg/lO0 ml), lactate (1105 mg/lO0 ml), and osmolality (551 mOsm/kg) were higher than previously associated with intake depression. However, synthetic juice with volatile fatty acids, lactate, soluble carbohydrate, pH, osmolality, ammonia, nitrite, and nitrate identical to the Silage juice accounted for only a maximum of 40% of its intake depressing effect when similarly infused. Other factors, such as amines, may have contributed to the depressing effects of the Silage juice on intake.