Ribeiro GO, Swift ML, McAllister TA. Effect of diastatic power and processing index on the feed value of barley grain for finishing feedlot cattle.
J Anim Sci 2017;
94:3370-3381. [PMID:
27695794 DOI:
10.2527/jas.2015-0068]
[Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The objective of this study was to assess the nutritional value of barley grain differing in diastatic power (DP; high vs. low; a malt trait) and processing index (PI; 75 vs. 85). One hundred sixty Angus × Hereford crossbred yearling steers (467 ± 38 kg; 144 intact and 16 rumen cannulated) were used in a complete randomized 2 × 2 factorial experiment. Steers were assigned to 16 pens, 8 of which were equipped with the GrowSafe system to measure individual feed intake. Cannulated steers (2 per pen) were randomly assigned to the 8 GrowSafe pens. Diets consisted of high- or low-DP barley grain (80.0% of diet DM) processed to an index of either 75 or 85% (PI-75 and PI-85, respectively). Ruminal pH in cannulated steers was measured over four 5-d periods using indwelling electrodes. Fecal samples were collected every 28 d from the rectum of each steer to assess digestibility using AIA as a marker. No differences ( > 0.10) in rumen pH were observed among cattle as measured by the indwelling pH meters. However, lower ( < 0.05) rumen pH was observed for steers fed low- as opposed to high-DP barley in rumen samples collected just prior to feeding and measured in the laboratory. Intake of DM and OM were not affected ( ≥ 0.24) by DP but were lower ( < 0.01) with more severe processing (PI-75 vs. PI-85). Low-DP barley tended to exhibit higher ( = 0.09) total tract DM digestibility than high-DP barley. Steers fed PI-75 barley also had higher ( = 0.06) G:F and NEg. Digestibility of DM, OM, CP, NDF, and starch was higher ( < 0.05) for PI-75 barley than for PI-85 barley. Low-DP barley increased ( < 0.05) carcass dressing percentage by 0.5% compared with high-DP barley, with a lower PI tending to increase ( = 0.06) rib eye area. Compared with steers fed high-DP diets, steers fed low-DP diets had more ( = 0.01) total (41.7 vs. 19.4%) and severe liver abscesses (22.2 vs. 9.7%). Results suggest that although low-DP barley increased liver abscesses, differences in DP did not alter digestion or growth performance but low-DP barley did improve dressing percentage. Barley with different DP responded similarly to processing, with more intensive processing (PI-75) of barley improving starch digestion, feed efficiency, and NEg without negatively affecting rumen pH.
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