The effect of feed processing on ruminal parameters in intensively fattened lambs

The aim of the study was to assess the influence of three processing ways of the concentrate feed on ruminal dry matter degradability, ruminal pH and ruminal protozoa population. Pelleted concentrate feed was mechanically processed to a particle size of phi 5 mm (variant A), ground at phi 2 mm (variant B) or by replacing the 50% of ground corn grain with expanded corn with phi 2 mm particle size as in B (variant C). The trial was carried out alternately on three lambs during their 90-132 days of life fitted with ruminal fistula. Feed bags and ruminal fluid was collected through the ruminal cannula at 3, 6, 9, 12, and 24 hours of incubation. After 24 hours of incubation the intra-ruminal feed concentrate dry matter degradation was significantly higher in expanded concentrate compared to pelleted concentrate (80.81% vs. 70.48%, P<0.049). The same parameter had an intermediary value of 77.85% for ground feed concentrate. Reducing pH value of the ruminal fluid from values of over 5.7 to an average of 5.3 resulted in reduction of the protozoa number per ml of ruminal fluid from 8.859 x 105 to 4.208 x 105. The lowest value for protozoa was obtained in variant A, 1.953 x 104 protozoa/ ml ruminal fluid, at a pH of 5.10 (following 6 hours of fermentation). It was concluded that out of all the identified protozoa, the Entodinium sp. was the dominant genus, making up 98.20% to 100% of the ruminal protozoa.