Intake, Duodenal Flow, and Ruminal Characteristics of Long or Short Chopped Alfalfa-Timothy Silage with or without Inoculant

¹ Agriculture Canada, C. P. 90, Lennoxville, PQ, J1M 123, Canada

Eight crossbred wethers each fitted with reentrant duodenal cannula and rumen fistula were used in a crossover design with a 2 x 2 factorial arrangement in order to measure the effects of inoculation and chop length of silage on intake, rate of flow into the duodenum, and ruminal characteristics. As chop length increased, silage DM decreased. Microbial inoculation had no effect on silage composition but increased its intake. Short chop length of silage decreased the amount of total N reaching the duodenum. The rumen acetate:propionate ratio was decreased by feeding the short vs. chopped silage. Rumen acetate concentration was lower when the sheep were fed short chopped silage compared with long chopped silage. Rumen volume and DM content were higher for sheep fed inoculated silages. The pH and NH₃ N of the rumen and rumen dilution rate of liquid and solids were similar for all treatments. Data show that microbial inoculation increased silage intake and that silage particle size modified duodenal flow of N and production of rumen VFA, which might alter performance of animals.

Key Words: silage • chop length • microbial inoculant

Submitted on February 13, 1990
Accepted on July 9, 1990