Abstract

This study was conducted to investigate the effects of alfalfa particle size (long vs. fine) and canola meal treated with hydrochloric acid solution (untreated vs treated) on ruminal chemical composition, liquid, particulate, escapable and non escapable phases in Zel sheep. Four ruminally cannulated sheep received a mixed diet (% of dry matter) consisting of 23.73 alfalfa, 8.70 canola meal, 39.56 wheat straw, 13.45 beet pulp and 13.45 barley grain and 1 mineral-vitamin mixture. The experimental design was a 4 × 4 Latin square with 22-days periods. The diet was offered twice daily (09:00 and 21:00 h). The rumens were evacuated manually at 3, 7.5 and 12 h post-feeding and total ruminal contents were separated into mat and liquids. Dry matter weight distribution of total recovered particles was determined by a wet-sieving procedure and used to partition ruminal mat and liquids among percentage of large (≥ 6.35 mm), medium (< 6.35 and ≥ 1.18 mm), and small (< 1.18 and ≥ 0.5 mm) particles. Lyophilized ruminal digesta were analyzed for chemical composition especially for CP, NDF and EE. No interactions (P > 0.05) between dietary particle size and acid level were observed for ruminal chemical composition, liquid, particulate, escapable and non escapable phase. Treatment of canola meal and increase of particle size reduced the values of CP. Generally, with increase in time after feeding, the values of each nutrient decreased. Particle size and time post-feeding had a pronounced effect on the distribution of different particle fractions, whereas acid level did not influence it. With increase in time after feeding, percentage of particles ≥ 6.35 mm decreased, whereas the percentage of particles < 6.35 mm increased, illustrating intensive particle breakdown in the reticulo-rumen. Different particle size and time post-feeding had pronounced effect on total mass of ruminal digesta, ruminal mat and liquid part, in which fine particles and 12 h post feeding caused the lowest rumen mat. Time post feeding and acid level did not influence the values of pH significantly, whereas with increase in particle size, the values of pH increased.

Key words: Canola meal, particle size, rumen mat, escapable, non escapable phase.

Abbreviation

CP, Crude protein; EE, ether extract; NDF, neutral detergent fiber;DM, dry matter.